CVE-2026-32762

NameCVE-2026-32762
DescriptionRack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21 and 3.2.0 to before 3.2.6, Rack::Utils.forwarded_values parses the RFC 7239 Forwarded header by splitting on semicolons before handling quoted-string values. Because quoted values may legally contain semicolons, a header can be interpreted by Rack as multiple Forwarded directives rather than as a single quoted for value. In deployments where an upstream proxy, WAF, or intermediary validates or preserves quoted Forwarded values differently, this discrepancy can allow an attacker to smuggle host, proto, for, or by parameters through a single header value. This issue has been patched in versions 3.1.21 and 3.2.6.
SourceCVE (at NVD; CERT, ENISA, 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+deb11u5vulnerable
bookworm2.2.20-0+deb12u1vulnerable
bookworm (security)2.2.22-0+deb12u1vulnerable
trixie3.1.18-1~deb13u1vulnerable
trixie (security)3.1.20-0+deb13u1vulnerable
forky3.1.18-1vulnerable
sid3.2.5-2vulnerable

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
ruby-racksourceexperimental3.2.6-1
ruby-racksource(unstable)(unfixed)

Notes

https://github.com/rack/rack/security/advisories/GHSA-qfgr-crr9-7r49
Fixed by: https://github.com/rack/rack/commit/27e06c695f3a47bdd9d21a1a7e8d97e12c52c255 (v3.2.6)
Fixed by: https://github.com/rack/rack/commit/9df5d34d4f496b22b8d07e919447e9dfa3240d41 (v3.1.21)

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