What’s Vulnerable › Vulnerabilities

CVE-2025-68142: PyMdown Extensions has ReDOS bug in Figure Capture extension

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-12-16 · updated 2026-06-17
• Weakness: CWE-1333

Description

PyMdown Extensions is a set of extensions for the `Python-Markdown` markdown project. Versions prior to 10.16.1 have a ReDOS bug found within the figure caption extension (`pymdownx.blocks.caption`). In systems that take unchecked user content, this could cause long hanges when processing the data if a malicious payload was crafted. This issue is patched in Release 10.16.1. As a workaround, those who process unknown user content without timeouts or other safeguards in place to prevent really large, malicious content being aimed at systems may avoid the use of `pymdownx.blocks.caption` until they're able to upgrade.

Affected products

• facelessuser pymdown-extensions: before 10.16.1 — fixed in 10.16.1

How to fix

Upgrade to a fixed version: facelessuser pymdown-extensions 10.16.1. Check the vendor advisory for mitigations.

References

• https://github.com/facelessuser/pymdown-extensions/commit/b50d15a56850ed1408a284bba81cc019c6bd72e8
• https://github.com/facelessuser/pymdown-extensions/security/advisories/GHSA-r6h4-mm7h-8pmq
• https://pypi.org/project/pymdown-extensions/10.16.1

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