CVE-2026-115352

CVSS 8.7 (high) · published 2026-10-22

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

Source: NVD CVE-2026-115352

References

• https://github.com/lepture/mistune/security/advisories/GHSA-xrpv-r66x-8p7j
• https://www.vulncheck.com/advisories/mistune-before-3.3.0-quadratic-time-dos-via-unmatched-brackets-in-inline-parser

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