CVE-2025-61772
highpriority · track · 0EPSS 0.009 · 60 %ileDEEUFRRUUSEPSS · scored 2026-10-27
Rack is a modular Ruby web server interface. In versions prior to 2.2.19, 3.1.17, and 3.2.2, `Rack::Multipart::Parser` can accumulate unbounded data when a multipart part’s header block never terminates with the required blank line (`CRLFCRLF`). The parser keeps appending incoming bytes to memory without a size cap, allowing a remote attacker to exhaust memory and cause a denial of service (DoS). Attackers can send incomplete multipart headers to trigger high memory use, leading to process termination (OOM) or severe slowdown. The effect scales with request size limits and concurrency. All applications handling multipart uploads may be affected. Versions 2.2.19, 3.1.17, and 3.2.2 cap per-part header size (e.g., 64 KiB). As a workaround, restrict maximum request sizes at the proxy or web server layer (e.g., Nginx `client_max_body_size`).
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- Fixedruby4.0-rubygem-rack-2.2-0:2.2.22-1.1.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".
- Fixedruby4.0-rubygem-rack-2.2-0:2.2.22-1.1.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".
- Fixedruby4.0-rubygem-rack-2.2-0:2.2.22-1.1.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".
- Fixedruby4.0-rubygem-rack-2.2-0:2.2.22-1.1.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".
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (51)
Products and version ranges known to be affected.
advisories (4)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2025-2482Red Hat Enterprise Linux: Mehrere Schwachstellen ermöglichen Denial of ServiceDeutsch2025-11-03csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Red Hat Enterprise Linux ausnutzen, um einen Denial of Service Angriff durchzuführen.
- openSUSE-SU-2026:10286-1ruby4.0-rubygem-rack-2.2-2.2.22-1.1 on GA media2026-03-04csaf · suse_csafDE
ruby4.0-rubygem-rack-2.2-2.2.22-1.1 on GA media
- GHSA-wpv5-97wm-hp9cRack's multipart parser buffers unbounded per-part headers, enabling DoS (memory exhaustion)2025-10-07ghsa · osvUS
## Summary `Rack::Multipart::Parser` can accumulate unbounded data when a multipart part’s header block never terminates with the required blank line (`CRLFCRLF`). The parser keeps appending incoming bytes to memory without a size cap, allowing a remote attacker to exhaust memory and cause a denial of service (DoS). ## Details While reading multipart headers, the parser waits for `CRLFCRLF` using: ```ruby @sbuf.scan_until(/(.*?\r\n)\r\n/m) ``` If the terminator never appears, it continues appending data (`@sbuf.concat(content)`) indefinitely. There is no limit on accumulated header bytes, so a single malformed part can consume memory proportional to the request body size. ## Impact Attackers can send incomplete multipart headers to trigger high memory use, leading to process termination (OOM) or severe slowdown. The effect scales with request size limits and concurrency. All applications handling multipart uploads may be affected. ## Mitigation * Upgrade to a patched Rack version that caps per-part header size (e.g., 64 KiB). * Until then, restrict maximum request sizes at the proxy or web server layer (e.g., Nginx `client_max_body_size`).
- CERTFR-2026-AVI-1352Multiples vulnérabilités dans Oracle PeopleSoftFrançais2026-10-21vendor · certfrFR
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (13)
External citations — patches, advisories, analysis.
- https://github.com/rack/rack/commit/589127f4ac8b5cf11cf88fb0cd116ffed4d2181ecnnvd
- https://github.com/rack/rack/commit/d869fed663b113b95a74ad53e1b5cae6ab31f29ecnnvd
- https://github.com/rack/rack/commit/e08f78c656c9394d6737c022bde087e0f33336fdcnnvd
- https://github.com/rack/rack/security/advisories/GHSA-wpv5-97wm-hp9ccnnvd
- https://vigilance.fr/vulnerability/Rack-five-vulnerabilities-dated-03-11-2025-48633cnnvd
- https://github.com/rack/rack/commit/589127f4ac8b5cf11cf88fb0cd116ffed4d2181eenisa_euvd
- https://github.com/rack/rack/commit/d869fed663b113b95a74ad53e1b5cae6ab31f29eenisa_euvd
- https://github.com/rack/rack/commit/e08f78c656c9394d6737c022bde087e0f33336fdenisa_euvd
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