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Fencer Vulns
medium 5.3

CVE-2026-61632 json

PyMdown Extensions: Path traversal in the b64 extension lets <img src> read files outside base_path

published 2026-07-24 3 mo ago modified 2026-10-24 15 d ago also GHSA-9xwg-3r6f-jcx2 , PYSEC-2026-3609 , EUVD-2026-54149

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi pymdown-extensions 11.0.0
  • pymdown-extensions Debian 14 11.0.1-1

debian advisories DEBIAN-CVE-2026-61632

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-61632 updated cvss 5.3

pymdown-extensions: PyMdown Extensions: Information disclosure via path traversal in b64 extension

  • Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-olm-catalogd-rhel9 Red Hat Self-service automation portal 2 ansible-automation-platform/bootc-automation-portal-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Hardened Images trivy 0.73.0-0.1.hum1, grafana12.4 12.4.7-0.1.hum1, grafana13.1 13.1.2-0.1.hum1
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/facelessuser/pymdown-extensions/security/advisories/GHSA-9xwg-3r6f-jcx2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
OSV 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi pymdown-extensions
<11.0.0
11.0.0

Affected products

  • facelessuser pymdown-extensions

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.