CVE-2026-71478

NameCVE-2026-71478
Descriptionleague/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a javascript: URL that browsers discard before parsing the scheme, causing the browser to still execute the script even when the unsafe-link filter is enabled. This issue is fixed in 2.9.0.
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
php-league-commonmark (PTS)bullseye1.5.7-2vulnerable
bookworm2.3.9-1+deb12u1vulnerable
trixie2.7.0-1+deb13u1vulnerable
forky, sid2.10.0-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
php-league-commonmarksource(unstable)2.9.0-1

Notes

[trixie] - php-league-commonmark <no-dsa> (Minor issue)
https://github.com/thephpleague/commonmark/security/advisories/GHSA-29pj-957v-52mc
Fixed by: https://github.com/thephpleague/commonmark/commit/493a5aa7d65754b73846006eaff9c2c4431a8e2c (2.9.0)

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