league/commonmark has an embed extension allowed_domains bypass
Summary
league/commonmark has an embed extension allowed_domains bypass
Original description
The description as published by the source.
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: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-33347 php-league-commonmark
- Ubuntu UBUNTU-CVE-2026-33347 php-league-commonmark Fixed in: 1.3.1-1ubuntu2+esm1
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- patch github.com
- web github.com