5.3

CVE-2025-68142: PyMdown Extensions has ReDOS bug in Figure Capture extension

Analyzed
AliasesGHSA-r6h4-mm7h-8pmqPYSEC-2026-1825UBUNTU-CVE-2025-68142
Published 16-12-2025Last modified 17-12-2025

Vulnerability summary

CVE-2025-68142 is a medium (CVSS 5.3) vulnerability in facelessuser pymdown_extensions. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 41.7% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Routine

Not severe (CVSS 2.7, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.3/10
010
Medium · v3.1 (NVD)
EPSS score
0.48%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Timeline

  1. 16-12-2025
    PublishedVulnerability first disclosed.
  2. 17-12-2025
    Last modifiedVulnerability information updated.

Description

PyMdown Extensions is a set of extensions for the `Python-Markdown` markdown project. Versions prior to 10.16.1 have a ReDOS bug found within the figure caption extension (`pymdownx.blocks.caption`). In systems that take unchecked user content, this could cause long hanges when processing the data if a malicious payload was crafted. This issue is patched in Release 10.16.1. As a workaround, those who process unknown user content without timeouts or other safeguards in place to prevent really large, malicious content being aimed at systems may avoid the use of `pymdownx.blocks.caption` until they're able to upgrade.

CVSS metrics

7 scores · 5 sources · 2 versions

EPSS trend

Probability

0.48%

Chance of exploitation in the next 30 days

Percentile

42%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.48% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Pymdown Extensions

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Facelessuser2 products
Debian1 product
  • pymdown-extensions< 10.13-1+deb13u1 | < 10.13-4
PyPI1 product
  • pymdown-extensions< 10.16.1
Ubuntu1 product
  • pymdown-extensionsAll versions (No fix recorded)

4 vendors · 5 products

References

10 links