CVE catalog
CVE-2026-71478
league/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
- Severity
- Medium · CVSS 6.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.36% · Oct 25, 2026
league/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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | php-league-commonmark | sid | 2.10.4-1 | fixed |
| Debian | php-league-commonmark | forky | 2.10.4-1 | fixed |
| Debian | php-league-commonmark | trixie | 2.7.0-1+deb13u1 | vulnerable |
| Debian | php-league-commonmark | bookworm | 2.3.9-1+deb12u1 | vulnerable |
| Composer | league/commonmark | Not reported | 2.9.0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | php-league-commonmark | source | sid | 2.9.0-1 | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | forky | 2.9.0-1 | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Composer | league/commonmark | composer | Not reported | 2.9.0 | Not reported | Not reported | Not reported |
Notes
[trixie] php-league-commonmark: Minor issue [bookworm] php-league-commonmark: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [php-league-commonmark]Affected
Details (2)
2.3.9-1+deb12u1· all · bookwormAffected
nvd · php-league-commonmark · debian · bookworm; nvd · php-league-commonmark · debian · 12
2.3.9-1+deb12u1· all · bookwormAffected
nvd · php-league-commonmark · debian · bookworm; nvd · php-league-commonmark · debian · 12
[Debian 13 (Trixie)]
- [php-league-commonmark]Affected
Details (2)
2.7.0-1+deb13u1· all · trixieAffected
nvd · php-league-commonmark · debian · 13
2.7.0-1+deb13u1· all · trixieAffected
nvd · php-league-commonmark · debian · 13
Observed:
References
- [https://github.com/advisories/GHSA-29pj-957v-52mc]
- [https://github.com/thephpleague/commonmark/commit/493a5aa7d65754b73846006eaff9c2c4431a8e2c]
- [https://github.com/thephpleague/commonmark/releases/tag/2.9.0]
- [https://github.com/thephpleague/commonmark/security/advisories/GHSA-29pj-957v-52mc]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-71478]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-71478]
- [https://security-tracker.debian.org/tracker/CVE-2026-71478]
[Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]