CVE-2026-105830

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductLeague/commonmark

PublishedOct 8, 2026

First seenOct 8, 2026

Weakness typeCWE-400Uncontrolled resource consumption

How to fix

Update

league/commonmark2.10.2 or later

Vendor advisories

github.com/thephpleague/commonmark/security/advisories/GHSA-3q6v-r5mr-hxv8

Affected products

Product	Affected versions	Fixed in
league/commonmarkPackagist	2.0.0 ≤ v < 2.10.2	2.10.2

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