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Fencer Vulns
medium 4.3

CVE-2026-46338 json

PyMdown Extensions: Regression in pymdownx.snippets reintroduces sibling-prefix path traversal bypass despite restrict_base_path

published 2026-05-19 5 mo ago modified 2026-10-24 15 d ago also EUVD-2026-45003 , GHSA-62q4-447f-wv8h , PYSEC-2026-2999

cvss
4.3
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. From 10.0.1 until 10.21.3, pymdownx.snippets uses a string-prefix containment check in SnippetPreprocessor.get_snippet_path() in pymdownx/snippets.py when `restrict_base_path: True`, allowing markdown snippet directives to read files from sibling paths that share the same base_path prefix, such as docs and docs_internal. This is a regression of CVE-2023-32309. This issue is fixed in version 10.21.3.

Patch / fix

  • pypi pymdown-extensions 10.21.3
  • facelessuser pymdown_extensions 10.21.3
  • pymdown_extensions_project pymdown_extensions 10.21.3
  • pymdown-extensions Debian 14 11.0.1-1

debian advisories DEBIAN-CVE-2026-46338

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-2026-46338 updated cvss 4.3

pymdown-extensions: PyMdown Extensions: Information disclosure via crafted Markdown snippets

  • 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: workaround, no fix available “Ensure that untrusted Markdown content is not processed by the pymdownx.snippets extension. If the snippets feature is not required, it can be disabled in the MkDocs or Python-Markdown configuration.”
  • Red Hat Hardened Images trivy 0.72.0-0.1.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
no
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-62q4-447f-wv8h referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
OSV 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi pymdown-extensions
>=10.0.1, <10.21.3
10.21.3

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.