CVE catalog
CVE-2026-30838
league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowe
- Severity
- Medium · CVSS 5.1
- Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.23% · Oct 25, 2026
league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing >. For example, <script\n> would pass through unfiltered and be rendered as a valid HTML tag by browsers. This is a cross-site scripting (XSS) vector for any application that relies on this extension to sanitize untrusted user input. All applications using the DisallowedRawHtml extension to process untrusted markdown are affected. Applications that use a dedicated HTML sanitizer (such as HTML Purifier) on the rendered output are not affected. This issue has been patched in version 2.8.1.
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 | fixed |
| Debian | php-league-commonmark | bookworm | 2.3.9-1+deb12u1 | fixed |
| Composer | league/commonmark | Not reported | 2.8.1 | fixed |
| Cpe | php-league-commonmark | Not reported | Not reported | vulnerable |
| Cpe | php-league-commonmark | Not reported | 2.4.2-2ubuntu0.1~esm1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | php-league-commonmark | source | sid | 2.8.1-1 | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | forky | 2.8.1-1 | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | trixie | 2.7.0-1+deb13u1 | not yet assigned | Not reported | Not reported |
| Debian | php-league-commonmark | source | bookworm | 2.3.9-1+deb12u1 | not yet assigned | Not reported | Not reported |
| Composer | league/commonmark | composer | Not reported | 2.8.1 | Not reported | Not reported | Not reported |
| Cpe | php-league-commonmark | cpe | Not reported | 2.4.2-2ubuntu0.1~esm1 | Not reported | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [php-league-commonmark]Fixed
Details (2)
2.3.9-1+deb12u1· all · bookwormFixed · Fixed:
2.3.9-1+deb12u1nvd · php-league-commonmark · debian · bookworm; nvd · php-league-commonmark · debian · 12
2.3.9-1+deb12u1· all · bookwormFixed · Fixed:
2.3.9-1+deb12u1nvd · php-league-commonmark · debian · bookworm; nvd · php-league-commonmark · debian · 12
[Debian 13 (Trixie)]
- [php-league-commonmark]Fixed
Details (2)
2.7.0-1+deb13u1· all · trixieFixed · Fixed:
2.7.0-1+deb13u1nvd · php-league-commonmark · debian · 13
2.7.0-1+deb13u1· all · trixieFixed · Fixed:
2.7.0-1+deb13u1nvd · php-league-commonmark · debian · 13
Observed:
References
- [https://github.com/advisories/GHSA-4v6x-c7xx-hw9f]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-30838]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-30838]
- [https://security-tracker.debian.org/tracker/CVE-2026-30838]
- [https://ubuntu.com/security/notices/USN-8194-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-1001.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Ubuntu Security Notices (USN)]