CVE-2026-61632

PyMdown Extensions is a set of extensions for the Python-Markdown markdown project. In versions up to and including 10.21.3, the b64 extension is vulnerable to a path traversal that discloses arbitrary files: it inlines images referenced by <img src="..."> by joining the src onto the configured base_path with os.path.normpath and opening the result directly, without verifying that the resolved path stays inside base_path. As a result, an src containing ../ sequences or an absolute path reads a file outside base_path as long as it has an allowed image extension (.png, .jpg, .jpeg, .gif, .svg), and the file's contents are then base64-encoded into the rendered output, disclosing them. An application that renders untrusted Markdown with pymdownx.b64 enabled can therefore leak the contents of image-extension files readable by the process to whoever controls the Markdown or views the output, a targeted file-read bounded by the extension check. This issue has been fixed in version 11.0.

CVSS 3.1

5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 34% of CVEs (scores of 2026-10-25)

CWE

CWE-22

Published

2026-08-06

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

Packages (OSV)

References

• https://github.com/facelessuser/pymdown-extensions/releases/tag/11.0
• https://github.com/facelessuser/pymdown-extensions/security/advisories/GHSA-9xwg-3r6f-jcx2
• https://github.com/facelessuser/pymdown-extensions/security/advisories/GHSA-9xwg-3r6f-jcx2

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