Description
League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone <script or <iframe line followed by a block supplying attributes like src or onload, executing stored scripts in viewers' browsers under default GFM settings.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| thephpleague | commonmark | — | — |
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 | 2.10.3-1 | — |
| Debian 13 | php-league-commonmark | No fix yet | — |
| Debian 12 | php-league-commonmark | No fix yet | — |
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 | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | php-league-commonmark | No fix yet | — |
| Ubuntu Pro 22.04 LTS | php-league-commonmark | No fix yet | — |
| Ubuntu Pro 20.04 LTS | php-league-commonmark | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Packagist | league/commonmark | >= 1.3.0, < 2.10.2 | 2.10.2 | GHSA-97jj-33gv-5xf9 |
References
- GitHub Security Advisory (GHSA-97jj-33gv-5xf9) vendor-advisory
- VulnCheck Advisory: League CommonMark 1.3.0 before 2.10.2 Stored XSS via DisallowedRawHtml Bypass third-party-advisory