CVE-2026-33170

NameCVE-2026-33170
DescriptionActive Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `SafeBuffer#%` does not propagate the `@html_unsafe` flag to the newly created buffer. If a `SafeBuffer` is mutated in place (e.g. via `gsub!`) and then formatted with `%` using untrusted arguments, the result incorrectly reports `html_safe? == true`, bypassing ERB auto-escaping and possibly leading to XSS. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
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)
Debian Bugs1132035

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
rails (PTS)bullseye2:6.0.3.7+dfsg-2+deb11u2vulnerable
bullseye (security)2:6.0.3.7+dfsg-2+deb11u4vulnerable
bookworm, bookworm (security)2:6.1.7.10+dfsg-1~deb12u2vulnerable
trixie (security), trixie2:7.2.2.2+dfsg-2~deb13u1vulnerable
forky2:7.2.3+dfsg-3vulnerable
sid2:7.2.3.1+dfsg-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
railssource(unstable)2:7.2.3.1+dfsg-11132035

Notes

[trixie] - rails <no-dsa> (Minor issue)
[bookworm] - rails <no-dsa> (Minor issue)
https://github.com/rails/rails/security/advisories/GHSA-89vf-4333-qx8v
Fixed by: https://github.com/rails/rails/commit/50d732af3b7c8aaf63cbcca0becbc00279b215b7 (v8.1.2.1)
Fixed by: https://github.com/rails/rails/commit/6e8a81108001d58043de9e54a06fca58962fc2db (v8.0.4.1)
Fixed by: https://github.com/rails/rails/commit/c1ad0e8e1972032f3395853a5e99cea035035beb (v7.2.3.1)

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