CVE-2026-34543

highpriority · track · 30EPSS 0.005 · 41 %ileDEEUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.48% (41st) EPSS
CVSS 7.5 · high
Is it mine?
8 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · osv · nvd

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, sensitive information from heap memory may be leaked through the decoded pixel data (information disclosure). This occurs under default settings; simply reading a malicious EXR file is sufficient to trigger the issue, without any user interaction. 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.

8.7
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.5–8.7

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 3.6
v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:Nsecondary · SUSE Product Security
v4.08.7highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:Nsecondary · ENISA EU
v4.08.7highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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
v4.06.6mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

05

affected products (8)

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-vc68-257w-m432OpenEXR: Heap information disclosure in PXR24 decompression via unchecked decompressed size (undo_pxr24_impl)2026-04-03ghsa · osvUS

    ### Summary The PXR24 decompression function undo_pxr24_impl in OpenEXR (internal_pxr24.c) ignores the actual decompressed size (outSize) returned by exr_uncompress_buffer() and instead reads from the scratch buffer based solely on the expected size (uncompressed_size) derived from the header metadata. Additionally, exr_uncompress_buffer() (compression.c:202) treats LIBDEFLATE_SHORT_OUTPUT (where the compressed stream decompresses to fewer bytes than expected) as a successful result rather than an error. When these two issues are combined, an attacker can craft a PXR24 EXR file containing a valid but truncated zlib stream. As a result, the decoder reads uninitialized heap memory and incorporates it into the output pixel data. ### Details This issue occurs due to the combination of two flaws. 1. compression.c:202–205 — LIBDEFLATE_SHORT_OUTPUT treated as success ``` else if (res == LIBDEFLATE_SHORT_OUTPUT) { /* TODO: is this an error? */ return EXR_ERR_SUCCESS; } ``` libdeflate_zlib_decompress_ex() returns LIBDEFLATE_SHORT_OUTPUT when the compressed stream is successfully decompressed but the resulting output size is smaller than the provided output buffer size. In this case, the actual number of decompressed bytes is written to actual_out. However, the function does not treat this condition as an error and instead returns success. 2. internal_pxr24.c:279–287 — outSize return value ignored ``` rstat = exr_uncompress_buffer( decode->context, compressed_data, comp_buf_size, scratch_data, scratch_size, &outSize); // outSize = actual bytes written if (rstat != EXR_ERR_SUCCESS) return rstat; // outSize is never referenced afterwards. // The loop below reads the entire scratch_data buffer based on // uncompressed_size (the header-derived expected size). for (int y = 0; y < decode->chunk.height; ++y) { ... } ``` After exr_uncompress_buffer() returns success, the code does not verify whether the actual decompressed size (outSize) matches the expected size (uncompressed_size). The subsequent byte-plane reconstruction loop reads from the scratch buffer up to uncompressed_size bytes. As a result, the region between outSize and uncompressed_size consists of uninitialized heap memory, which is then read by the decoder. **Affected component** - src/lib/OpenEXRCore/internal_pxr24.c — undo_pxr24_impl() (line 261–399) - src/lib/OpenEXRCore/compression.c — exr_uncompress_buffer() (line 202–205) ### PoC Please refer to the atta [poc.zip](https://github.com/user-attachments/files/26002361/poc.zip) ched archive file and proceed after extracting it. 1. git clone https://github.com/AcademySoftwareFoundation/openexr.git 2. mv poc openexr/ 3. cd openexr 4. docker build -f poc/Dockerfile -t pxr24-poc . 5. docker run --rm pxr24-poc <img width="858" height="155" alt="스크린샷 2026-03-15 오후 4 38 18" src="https://github.com/user-attachments/assets/ded9eab6-9b92-40f7-9a0d-7b00db7e6088" /> ### Impact * Sensitive information from heap memory may be leaked through the decoded pixel data (information disclosure). Trigger Condition: Occurs under default settings; simply reading a malicious EXR file is sufficient to trigger the issue, without any user interaction.

  • PYSEC-2026-2850OpenEXR: Heap information disclosure in PXR24 decompression via unchecked decompressed size (undo_pxr24_impl)2026-07-13vendor · osvUS

    ### Summary The PXR24 decompression function undo_pxr24_impl in OpenEXR (internal_pxr24.c) ignores the actual decompressed size (outSize) returned by exr_uncompress_buffer() and instead reads from the scratch buffer based solely on the expected size (uncompressed_size) derived from the header metadata. Additionally, exr_uncompress_buffer() (compression.c:202) treats LIBDEFLATE_SHORT_OUTPUT (where the compressed stream decompresses to fewer bytes than expected) as a successful result rather than an error. When these two issues are combined, an attacker can craft a PXR24 EXR file containing a valid but truncated zlib stream. As a result, the decoder reads uninitialized heap memory and incorporates it into the output pixel data. ### Details This issue occurs due to the combination of two flaws. 1. compression.c:202–205 — LIBDEFLATE_SHORT_OUTPUT treated as success ``` else if (res == LIBDEFLATE_SHORT_OUTPUT) { /* TODO: is this an error? */ return EXR_ERR_SUCCESS; } ``` libdeflate_zlib_decompress_ex() returns LIBDEFLATE_SHORT_OUTPUT when the compressed stream is successfully decompressed but the resulting output size is smaller than the provided output buffer size. In this case, the actual number of decompressed bytes is written to actual_out. However, the function does not treat this condition as an error and instead returns success. 2. internal_pxr24.c:279–287 — outSize return value ignored ``` rstat = exr_uncompress_buffer( decode->context, compressed_data, comp_buf_size, scratch_data, scratch_size, &outSize); // outSize = actual bytes written if (rstat != EXR_ERR_SUCCESS) return rstat; // outSize is never referenced afterwards. // The loop below reads the entire scratch_data buffer based on // uncompressed_size (the header-derived expected size). for (int y = 0; y < decode->chunk.height; ++y) { ... } ``` After exr_uncompress_buffer() returns success, the code does not verify whether the actual decompressed size (outSize) matches the expected size (uncompressed_size). The subsequent byte-plane reconstruction loop reads from the scratch buffer up to uncompressed_size bytes. As a result, the region between outSize and uncompressed_size consists of uninitialized heap memory, which is then read by the decoder. **Affected component** - src/lib/OpenEXRCore/internal_pxr24.c — undo_pxr24_impl() (line 261–399) - src/lib/OpenEXRCore/compression.c — exr_uncompress_buffer() (line 202–205) ### PoC Please refer to the atta [poc.zip](https://github.com/user-attachments/files/26002361/poc.zip) ched archive file and proceed after extracting it. 1. git clone https://github.com/AcademySoftwareFoundation/openexr.git 2. mv poc openexr/ 3. cd openexr 4. docker build -f poc/Dockerfile -t pxr24-poc . 5. docker run --rm pxr24-poc <img width="858" height="155" alt="스크린샷 2026-03-15 오후 4 38 18" src="https://github.com/user-attachments/assets/ded9eab6-9b92-40f7-9a0d-7b00db7e6088" /> ### Impact * Sensitive information from heap memory may be leaked through the decoded pixel data (information disclosure). Trigger Condition: Occurs under default settings; simply reading a malicious EXR file is sufficient to trigger the issue, without any user interaction.

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published 2026-04-01modified 2026-10-26
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