CVE-2026-126063

NameCVE-2026-126063
DescriptionNokogiri is an open source XML and HTML library for the Ruby programming language. From 1.12.0 until 1.19.5, the C extension on CRuby and TruffleRuby has a Nokogiri::HTML5 serializer that does not escape text inside noscript elements or angle brackets inside attribute values. When an application sanitizes untrusted HTML with the default parsing options, allows noscript, and sends serialized output to a scripting-enabled browser, the browser can parse markup that Nokogiri did not produce, enabling mutation cross-site scripting. Using parse_noscript_content_as_text: true is the recommended workaround, not the vulnerable default. JRuby is not affected because it does not implement Nokogiri::HTML5. This issue is fixed in version 1.19.5.
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-nokogiri (PTS)bookworm1.13.10+dfsg-2vulnerable
trixie1.18.2+dfsg-1vulnerable
forky1.19.4+dfsg-1vulnerable
sid1.19.7+dfsg-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
ruby-nokogirisource(unstable)1.19.7+dfsg-1

Notes

https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-4p39-36wj-23h4
Fixed by: https://github.com/sparklemotion/nokogiri/commit/c6c0bffbdcd194694995acafeeed27326b0805f8 (v1.19.5)

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