# CVE-2026-71488: php-league-commonmark: league/commonmark is a PHP library for parsing and rendering CommonMark Markdown

CVE-2026-71488 is fixed in php-league-commonmark on 1 platform by DEBIAN-CVE-2026-71488 (version 2.9.0-1), released August 11, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-71488
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0063
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 6, 2026

## Description

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translate between character positions and byte positions, and the Autolink extension can also copy and validate the remaining line at every URL-like prefix, allowing an attacker who can submit Markdown for conversion to consume disproportionate CPU time with a comparatively small request. This issue is fixed in 2.9.0.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | php-league-commonmark Debian 14 | 2.9.0-1 | [DEBIAN-CVE-2026-71488](https://patchblox.com/security/data/fix/linux/debian-cve-2026-71488.md) | Aug 11, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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