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CVE-2026-115352GHSA-XRPV-R66X-8P7JEUVD-2026-108421GHSA-84GC-H84G-H8G5

Mistune before 3.3.0 Quadratic-Time DoS via Unmatched Brackets in Inline Parser

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 3.3.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

Mistune before 3.3.0 contains an algorithmic complexity vulnerability in the inline link parser that allows unauthenticated attackers to exhaust CPU by submitting long runs of unmatched '[' characters. Attackers can send small markdown payloads that trigger O(N^2) parse_link_text and parse_link_label probing, occupying rendering workers for 30+ seconds per 16 KB input.

Timeline

  1. CVE published
  2. First seen by cve.now
  3. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  4. Record last updated

Affected versions

  • lepture mistune

    fixed in 3.3.0

References 2

GitHub · lepture/mistune

vulncheck.com