> CVE-2026-67422 [HIGH]

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PUBLISHED
2026-08-06 22:18
MODIFIED
2026-08-06 22:18
CVSS_SCORE V3
7.5
EPSS (Prob. Exploit)
0.61%
Top 50.9%
DATA SOURCES:
NVD 🔗 2026-08-06 RED HAT 🔗 2026-08-07 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-11-01 GITHUB 🔗 2026-10-15 OSV 🔗 2026-10-26

> DESCRIPTION

pymdown-extensions is a collection of extensions for the Python Markdown library. In versions up to and including 11.0, four inline processors (caret, tilde, betterem, and magiclink) use regular expressions whose content groups can partition a run of delimiter characters in exponentially many ways, causing catastrophic backtracking. As a result, a single untrusted Markdown line under 50 bytes rendered with markdown.markdown() in each extension's default configuration drives the rendering thread into unbounded CPU usage that grows exponentially with input length, enabling an unauthenticated remote attacker who can submit Markdown to cause denial of service. The exposure is concrete for web applications that render user-supplied Markdown (comments, wikis, issue bodies, live preview), including any app using pymdownx.extra which bundles the vulnerable betterem default, as well as hosted docs/CI systems that build untrusted Markdown. The issue has been fixed in version 11.0.1.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EXPLOITABILITY
3.9
IMPACT
3.6

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
None (N)
Aucune divulgation d'informations
I (Impact Intégrité)
Integrity Impact
None (N)
Aucune modification de données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
None
Aucune divulgation d'informations
Intégrité
None
Aucune modification de données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-1333

> CWE DETAILED DESCRIPTIONS

CWE-1333: Inefficient Regular Expression Complexity - The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: Ansible automation portal Red Hat Enterprise Linux Images
Updated images are now available for Red Hat Ansible Automation Platform 2.2, which include new features, bug fixes, and enhancements for the Red Hat Ansible Automation Portal bootable container image...
Red Hat Security Advisory: Red Hat Developer Hub 1.9.9 release.
Red Hat Developer Hub 1.9.9 has been released.
Red Hat Security Advisory: Red Hat Developer Hub 1.10.5 release.
Red Hat Developer Hub 1.10.5 has been released.

> RED HAT SEVERITY ASSESSMENT

THREAT SEVERITY
Important

> GITHUB SECURITY ADVISORY

GHSA-gm37-52c6-37mw HIGH

pymdown-extensions: exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

AFFECTED PACKAGES:
PIP / pymdown-extensions
<= 11.0.0
Fixed in: 11.0.1

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

pymdown-extensions: Exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

AFFECTED PACKAGES:
Unknown / Unknown
112 versions affected
ALIASES:
GHSA-gm37-52c6-37mw, PYSEC-2026-3654

> HISTORIQUE DES MODIFICATIONS

Première apparition
06/08/2026 22:18
Source: NVD
📊 ENRICHISSEMENT 01/09/2026 06:02
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-1333: Inefficient Regular Expression Complexity - The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
📊 ENRICHISSEMENT 07/08/2026 23:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 22:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 21:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 20:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 19:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 18:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 17:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 16:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 15:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 14:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 13:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 12:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
N/A
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 07/08/2026 12:30
REDHAT
Champ modifié: Red Hat
Ancienne valeur:
Non
Nouvelle valeur:
Oui
Total des modifications: 14 Dernière mise à jour: 2 months ago

> REFERENCES

https://github.com/facelessuser/pymdown-extensions/commit/c68498598d7b13011bb457...
https://github.com/facelessuser/pymdown-extensions/security/advisories/GHSA-gm37...
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