CVE-2026-115352 Mistune before 3.3.0 Quadratic-Time DoS via Unmatched Brackets in Inline Parser
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-115352?
CVE-2026-115352 is a high-severity vulnerability in lepture mistune, published on 22 Oct 2026.
Official 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.
Weakness: CWE-407
Which versions are affected by CVE-2026-115352?
How do I fix CVE-2026-115352?
No fix has been published for CVE-2026-115352 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-115352 being exploited?
There is no known exploitation of CVE-2026-115352 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-115352, GHSA-84gc-h84g-h8g5, GHSA-xrpv-r66x-8p7j, UBUNTU-CVE-2026-115352.