CVE-2026-115347 Mistune before 3.3.0 Quadratic Denial of Service via parse_link_text
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-115347?
CVE-2026-115347 is a high-severity vulnerability in lepture mistune, published on 22 Oct 2026.
Official description
Mistune before 3.3.0 contains an inefficient algorithmic complexity vulnerability in parse_link_text that allows remote attackers to cause denial of service through unbalanced square brackets. Attackers can submit markdown containing long runs of unmatched brackets to mistune.html(), triggering repeated forward scans that stall worker processes for minutes.
Weakness: CWE-407
Which versions are affected by CVE-2026-115347?
How do I fix CVE-2026-115347?
No fix has been published for CVE-2026-115347 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-115347 being exploited?
There is no known exploitation of CVE-2026-115347 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-115347, GHSA-8xqv-hm62-6r4g, GHSA-f32h-38gf-rg5r, UBUNTU-CVE-2026-115347.