CVE-2025-61772

NameCVE-2025-61772
DescriptionRack 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`).
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
ruby-rack (PTS)bullseye2.1.4-3+deb11u2vulnerable
bullseye (security)2.1.4-3+deb11u3vulnerable
bookworm, bookworm (security)2.2.13-1~deb12u1vulnerable
forky, sid, trixie3.1.16-0.1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
ruby-racksource(unstable)(unfixed)

Notes

https://github.com/rack/rack/security/advisories/GHSA-wpv5-97wm-hp9c
Fixed by: https://github.com/rack/rack/commit/589127f4ac8b5cf11cf88fb0cd116ffed4d2181e (v3.2.2)
Fixed by: https://github.com/rack/rack/commit/e08f78c656c9394d6737c022bde087e0f33336fd (v3.1.17)
Fixed by: https://github.com/rack/rack/commit/d869fed663b113b95a74ad53e1b5cae6ab31f29e (v2.2.19)

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