What’s Vulnerable › Vulnerabilities

CVE-2026-105830: league/commonmark 2.0.0 before 2.10.2 Quadratic DoS via TableStartParser

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-08 · updated 2026-10-08
• Weakness: CWE-400

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

• thephpleague commonmark: from 2.0.0 before 2.10.2 — fixed in 2.10.2

How to fix

Upgrade to a fixed version: thephpleague commonmark 2.10.2. Check the vendor advisory for mitigations.

References

• https://github.com/thephpleague/commonmark/security/advisories/GHSA-3q6v-r5mr-hxv8
• https://www.vulncheck.com/advisories/league-commonmark-2.0.0-before-2.10.2-quadratic-dos-via-tablestartparser
• https://github.com/thephpleague/commonmark/security/advisories/GHSA-3q6v-r5mr-hxv8

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