MEDIUMCVSS v3.1 5.3Vulnerability
CVE-2026-121438
Mistune before 3.3.3 contains a denial of service vulnerability in InlineParser.parse_link that allows attackers to cause quadratic CPU growth by supplying balanced nested brackets. Attackers can submit crafted Markdown with thousands of nested bracket pairs not forming a valid link, triggering repeated _contains_nested_link scans that exhaust CPU in parsing applications.
Properties
- Severity
- MEDIUM
- Nvd fetched at
- 2026-11-03T17:20:13.885968+00:00
- Cvss score
- 5.3
- Cvss severity
- MEDIUM
- Retrieved at
- 2026-11-03T17:21:18+00:00
- Score
- 5.3
- Last source
- NVD
- Cvss version
- 3.1
- Cve id
- CVE-2026-121438
- Cvss vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- First seen by Signal
- 2026-11-03T17:21:18+00:00
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Published at
- 2026-11-03T15:17:35.330
- Last modified
- 2026-11-03T15:17:35.457
Related Entities (1)
HAS_WEAKNESS (1)
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