Description
league/commonmark from 2.0.0 before 2.10.2 contains a quadratic-time denial of service vulnerability in the GitHub Flavored Markdown Table extension's TableStartParser::tryStart() block-start scan. Unauthenticated attackers can submit a large paragraph of pipe-free lines not starting with letters, forcing repeated full-buffer strpos scans that exhaust PHP worker CPU.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| thephpleague | commonmark | 2.0.0 – < 2.10.2 | 2.10.2 |
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 | 2.10.3-1 | — |
| 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 | >= 2.0.0, < 2.10.2 | 2.10.2 | GHSA-3q6v-r5mr-hxv8 |
References
- GitHub Security Advisory (GHSA-3q6v-r5mr-hxv8) vendor-advisory
- VulnCheck Advisory: league/commonmark 2.0.0 before 2.10.2 Quadratic DoS via TableStartParser third-party-advisory