HIGH 7.5

PYSEC-2026-2216

Quick fix

PYSEC-2026-2216 — mistune: upgrade to the fixed version with the command below.

pip install --upgrade 'mistune>=3.3.0'

Details

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes quadratic work in src/mistune/block_parser.py and the ref_links environment dictionary handling, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.

Are you affected?

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Affected packages

PyPI / mistune

Introduced in: 0 Fixed in: 3.3.0

Fix pip install --upgrade 'mistune>=3.3.0'

References

https://github.com/lepture/mistune/releases/tag/v3.3.0 [ADVISORY]
https://github.com/lepture/mistune/commit/2b04d7ba341c16ac78fe82d3076bdd5c3de87c69 [FIX]
https://github.com/lepture/mistune/security/advisories/GHSA-ffq3-xpv3-j92q [EVIDENCE]