CVE-2026-115352GHSA-xrpv-r66x-8p7j
Mistune before 3.3.0 Quadratic-Time DoS via Unmatched Brackets in Inline Parser
lepture mistune
CVSS
8.7HighExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.36%Chance of exploitation activity in the next 30 days, higher than 28% of CVEs. Scored 23 Oct 2026FIRST EPSS
What fixes it
- 3.3.0mistuneCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
Description
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.
Text from CVE List
Affected versions 2
- mistuneaffected: all versions before 3.3.0CVE List
- mistuneunaffected: 3.3.0CVE List