Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| thephpleague | commonmark | >= 1.5.0, <= 2.8.3 | — |
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 | 2.9.0-1 | — |
| 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 | markdown +1 | No fix yet | — |
| Ubuntu 26.04 LTS | markdown +1 | No fix yet | — |
| Ubuntu 24.04 LTS | markdown +1 | No fix yet | — |
| Ubuntu 22.04 LTS | markdown +1 | No fix yet | — |
| Ubuntu 20.04 LTS | markdown | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | markdown | No fix yet | — |
| Ubuntu 16.04 LTS | markdown | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Packagist | league/commonmark | >= 1.5.0, < 2.9.0 | 2.9.0 | GHSA-29pj-957v-52mc |