CVE-2026-33347

Name	CVE-2026-33347
Description	league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like youtube.com.evil passes the allowlist check when youtube.com is an allowed domain. This issue has been patched in version 2.8.2.
Source	CVE (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 Package	Release	Version	Status
php-league-commonmark (PTS)	bullseye	1.5.7-2	vulnerable
	bookworm	2.3.9-1	vulnerable
	trixie	2.7.0-1	vulnerable
	forky, sid	2.8.2-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
php-league-commonmark	source	(unstable)	2.8.2-1

Notes

[trixie] - php-league-commonmark <no-dsa> (Minor issue)
[bookworm] - php-league-commonmark <no-dsa> (Minor issue)
[bullseye] - php-league-commonmark <postponed> (Minor issue)
https://github.com/thephpleague/commonmark/security/advisories/GHSA-hh8v-hgvp-g3f5
Fixed by: https://github.com/thephpleague/commonmark/commit/59fb075d2101740c337c7216e3f32b36c204218b (2.8.2)