---
id: CVE-2026-105830
title: >-
  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
summary: >-
  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 …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
vendor: thephpleague
product: commonmark
affected:
  - commonmark >= 2.0.0 < 2.10.2
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:33:42.423'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-105830'
references:
  - url: >-
      https://github.com/thephpleague/commonmark/security/advisories/GHSA-3q6v-r5mr-hxv8
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/league-commonmark-2.0.0-before-2.10.2-quadratic-dos-via-tablestartparser
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/thephpleague/commonmark/security/advisories/GHSA-3q6v-r5mr-hxv8
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-08T17:03:04.954507Z'
ingestedAt: '2026-10-08T14:47:16.361Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.