CVE-2026-121437
Mistune from 3.3.0 before 3.3.4 contains a denial of service vulnerability that allows remote…
- Risk score
- 50/100
- CVSS
- 7.5 v3.1
- Published
- 3 Nov 2026
Open in the live forecast Today's forecast
What to know
- What it is
- Mistune from 3.3.0 before 3.3.4 contains a denial of service vulnerability that allows remote attackers to exhaust CPU through quadratic-time emphasis delimiter processing. Attackers can submit small markdown documents with repeated patterns like "*a_b" to trigger an O(n²) index-fixup loop, stalling workers for second…
- Affected
- See advisory
- Fix
- Upgrade the product to 3.3.4 or later.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 7.5 high
- Remotely exploitable without logging in
References
Original description
Mistune from 3.3.0 before 3.3.4 contains a denial of service vulnerability that allows remote attackers to exhaust CPU through quadratic-time emphasis delimiter processing. Attackers can submit small markdown documents with repeated patterns like "*a_b" to trigger an O(n²) index-fixup loop, stalling workers for seconds.
Last activity 3 Nov 2026. Patch Forecast updates every hour.