# CVE-2026-86430: php-league-commonmark: league/commonmark versions before 2.9.1 contain multiple denial of service vulnerabilities in fenced code block detec...

CVE-2026-86430 is fixed in php-league-commonmark on 1 platform by DEBIAN-CVE-2026-86430 (version 2.10.0-1), released September 8, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-86430
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 7, 2026

## Description

league/commonmark versions before 2.9.1 contain multiple denial of service vulnerabilities in fenced code block detection, reference link label lookup, and emphasis delimiter processing that perform super-linear work on crafted input. Attackers can submit specially crafted Markdown with long backtick runs, nested brackets, or delimiter sequences to consume disproportionate CPU time and prevent legitimate requests from completing.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | php-league-commonmark Debian 14 | 2.10.0-1 | [DEBIAN-CVE-2026-86430](https://patchblox.com/security/data/fix/linux/debian-cve-2026-86430.md) | Sep 8, 2026 |

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Data as of 2026-11-09T19:38:12Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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