CVE-2026-61632 PyMdown Extensions: Path traversal in the b64 extension lets <img src> read files outside base_path
Attackers can read arbitrary image files outside the base directory by exploiting path traversal in the b64 extension of PyMdown Extensions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-61632?
CVE-2026-61632 is a medium-severity path traversal vulnerability in facelessuser pymdown-extensions, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-22
Which versions are affected by CVE-2026-61632?
3 open source packages ship an affected version, including pymdown-extensions.
| Package | Affected | Fixed in |
|---|---|---|
pymdown-extensions PyPI | All versions | 11.0.0 |
pymdown-extensions PyPI | All versions | 11.0.0 |
pymdown-extensions PyPI | All versions | 11.0.0 |
How do I fix CVE-2026-61632?
Upgrade pymdown-extensions to 11.0.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-61632 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61632 exists.
Sources
Also known as DEBIAN-CVE-2026-61632, ECHO-d088-1f41-49db, GHSA-9xwg-3r6f-jcx2, PYSEC-2026-3609, UBUNTU-CVE-2026-61632.