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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| thephpleague | commonmark | >= 2.3.0, < 2.8.2 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | php-league-commonmark | 2.8.2-1 | — |
| Debian 13 | php-league-commonmark | 2.7.0-1+deb13u1 | — |
| Debian 12 | php-league-commonmark | 2.3.9-1+deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | php-league-commonmark | No fix yet | — |
| Ubuntu 26.04 LTS | php-league-commonmark | No fix yet | — |
| Ubuntu 25.10 | php-league-commonmark | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | php-league-commonmark | 2.4.2-2ubuntu0.1~esm1 | USN-8194-1 |
| Ubuntu Pro 22.04 LTS | php-league-commonmark | 1.6.7-1ubuntu0.1~esm1 | USN-8194-1 |
| Ubuntu Pro 20.04 LTS | php-league-commonmark | 1.3.1-1ubuntu2+esm1 | USN-8194-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Packagist | league/commonmark | >= 2.3.0, < 2.8.2 | 2.8.2 | GHSA-hh8v-hgvp-g3f5 |
Advisories 2
- USN-8194-1 php-league-commonmark vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- WID-SEC-2026-1001 Snipe-IT: Mehrere Schwachstellen ermöglichen Umgehen von Sicherheitsvorkehrungen und potenziell Cross-Site Scripting BSI CERT-Bund (WID) · Apr 7, 2026