PyMdown Extensions has ReDOS bug in Figure Capture extension
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Partial Red Hat: 15 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-1333.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| facelessuser | pymdown-extensions | before 10.16.1 | 10.16.1 | Patch available | CNA |
| — | pymdown-extensions (PyPI) | before 10.16.1 | 10.16.1 | Patch available | GHSA-r6h4-mm7h-8pmq |
- pymdown-extensions Vendorfacelessuser Affected before 10.16.1 Fixed in 10.16.1 Patch available CNA
- pymdown-extensions (PyPI) Vendor— Affected before 10.16.1 Fixed in 10.16.1 Patch available GHSA-r6h4-mm7h-8pmq
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:facelessuser:pymdown_extensions:*:*:*:*:*:*:*:* | before 10.16.1 | Vulnerable | facelessuser |
- cpe:2.3:a:facelessuser:pymdown_extensions:*:*:*:*:*:*:*:* Versions before 10.16.1 Vulnerable ·facelessuser
Remediation
- Fix · CNA pymdown-extensions (facelessuser) Fixed in 10.16.1
- Fix · GHSA-r6h4-mm7h-8pmq pymdown-extensions (PyPI) Fixed in 10.16.1 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Assisted Installer for Red Hat OpenShift Container Platform 2 | Affected | No fix yet: Fix deferred |
| External Secrets Operator for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Multicluster Engine for Kubernetes | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 2 | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 3 | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Security 4 | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 6 | Affected | No fix yet |
| Red Hat Ceph Storage 7 | Affected | No fix yet |
| Red Hat Ceph Storage 8 | Affected | No fix yet |
| Red Hat Ceph Storage 9 | Affected | No fix yet |
| Red Hat Developer Hub 1 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift GitOps | Affected | No fix yet: Fix deferred |
| external secrets operator for Red Hat OpenShift - Tech Preview | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2025-68142
- 2026-10-03 Alias added: GHSA-r6h4-mm7h-8pmq
- 2026-10-27 Affected versions changed · Red Hat
References
Patch 1
More facelessuser Pymdown Extensions vulnerabilities
- TI-2023-15603 Arbitrary file inclusion with the pymdowm-snippets extension CVSS 3.1HIGH 7.5
- TI-2026-34058 Path traversal in facelessuser pymdown-extensions CVSS 3.1MEDIUM 4.3
Sources
- CVE-2025-68142 · CVE Program
- CVE-2025-68142 · NVD
- FIRST EPSS
- GHSA-r6h4-mm7h-8pmq · GitHub Advisory Database · CC BY 4.0
- CVE-2025-68142 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences