CVE-2025-68142

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.

CVSS v3.1 Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weakness Type (CWE)

CWE-1333 CWE-1333

Affected Products

Vendor	Product	Versions
facelessuser	pymdown_extensions	< 10.16.1

References

Advisories & Patches

https://github.com/facelessuser/pymdown-extensions/commit/b50d15a56850ed1408a284bba81cc019c6bd72e8 https://github.com/facelessuser/pymdown-extensions/security/advisories/GHSA-r6h4-mm7h-8pmq

Exploits

https://github.com/facelessuser/pymdown-extensions/security/advisories/GHSA-r6h4-mm7h-8pmq

Other References

https://pypi.org/project/pymdown-extensions/10.16.1

Frequently Asked Questions

What is CVE-2025-68142? +

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. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2025-68142? +

CVE-2025-68142 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-68142? +

CVE-2025-68142 affects products from facelessuser, specifically: pymdown_extensions. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-68142? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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