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.
Published: 2026-08-06
Score: 5.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-9xwg-3r6f-jcx2 PyMdown Extensions: Path traversal in the b64 extension lets <img src> read files outside base_path
History

Fri, 07 Aug 2026 01:00:00 +0000

Type Values Removed Values Added
First Time appeared Facelessuser
Facelessuser pymdown Extensions
Vendors & Products Facelessuser
Facelessuser pymdown Extensions

Thu, 06 Aug 2026 22:15:00 +0000

Type Values Removed Values Added
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.
Title PyMdown Extensions: Path traversal in the b64 extension lets <img src> read files outside base_path
Weaknesses CWE-22
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}


Subscriptions

Facelessuser Pymdown Extensions
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-06T20:59:20.177Z

Reserved: 2026-07-10T17:38:57.111Z

Link: CVE-2026-61632

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-07T00:45:04Z

Weaknesses
  • CWE-22

    Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')