Duplicate Advisory: Mistune has a ReDoS in LINK_TITLE_RE that allows denial of service via crafted Markdown input

Severity: medium · CVSS 4 · Published 2026-05-06

Duplicate Advisory: Mistune has a ReDoS in LINK_TITLE_RE that allows denial of service via crafted Markdown input

Technologies: mistune (PyPI). Vendors: PyPI.

Quick answers

Is This vulnerability exploited in the wild?
No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?
Medium severity, with a CVSS score of 4, published 6 May 2026.
Which products and versions are affected?
mistune (PyPI) ECOSYSTEM:introduced=3.0.0a1,fixed=3.2.1.
Is there a fix for This vulnerability?
Yes. mistune (PyPI): upgrade to 3.2.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected?
Check whether you run mistune (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • mistune (PyPI): upgrade to 3.2.1 or later
    pip install "mistune>=3.2.1"

Affected products

  • mistune (PyPI) ECOSYSTEM:introduced=3.0.0a1,fixed=3.2.1

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