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CVE-2026-49851
UNKNOWN · CVSS n/a
EPSS exploitation probability: 0%
Published 2026-06-24T18:17:18.937 · Last modified 2026-06-24T18:17:18.937

Summary

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Mistune is vulnerable to a CPU exhaustion DoS due to superlinear (approximately O(n²)) behavior in parse_link_text. When parsing Markdown containing many consecutive [ characters, parse_link_text repeatedly scans the input using a regex search inside a loop. Each iteration re-scans a large portion of the remaining string, resulting in quadratic-time behavior. An attacker-controlled Markdown input can therefore trigger excessive CPU usage with a very small payload. This vulnerability is fixed in 3.3.0.

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.