> CVE-2026-91123 [HIGH]

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PUBLISHED
2026-09-24 17:17
MODIFIED
2026-09-24 17:17
CVSS_SCORE V3
7.2
EPSS (Prob. Exploit)
0.29%
Top 79.9%
DATA SOURCES:
NVD đź”— 2026-09-24 CWE MITRE đź”— 2026-10-01 FIRST EPSS đź”— 2026-10-22 OSV đź”— 2026-10-19

> DESCRIPTION

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the iframe src traversal guard did not treat literal backslashes as path separators after decoded dot segments. A crafted source could therefore pass an allowed_iframes subpath check while browser URL normalization moved the iframe outside the intended allowed path. The resulting iframe could load content from a location that the administrator did not allow. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.

> 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:C/C:L/I:L/A:N
EXPLOITABILITY
3.9
IMPACT
2.7

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
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
Changed (C)
Impact s'étend au-delà du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
Low (L)
Divulgation limitée d'informations
I (Impact Intégrité)
Integrity Impact
Low (L)
Modification limitée des données possible
A (Impact Disponibilité)
Availability Impact
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

Confidentialité
Low
Divulgation limitée d'informations
Intégrité
Low
Modification limitée des données possible
Disponibilité
None
Aucune interruption de service

> WEAKNESSES

CWE-22

> CWE DETAILED DESCRIPTIONS

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') - The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Discourse: Reject literal backslash path separators in iframe src traversal guard

AFFECTED PACKAGES:
Unknown / Unknown
21 versions affected
ALIASES:
BIT-discourse-2026-91123, GHSA-6pwj-wgg8-4rjc

> HISTORIQUE DES MODIFICATIONS

Première apparition
24/09/2026 17:17
Source: NVD
📊 ENRICHISSEMENT 01/10/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') - The product uses external input to construct a pathname that is intended to identify a file or directory that i...
Total des modifications: 1 Dernière mise à jour: 3 weeks ago

> REFERENCES

https://github.com/discourse/discourse/commit/042d7b159beda4f74d23e245e8b2e396d9...
https://github.com/discourse/discourse/commit/097ce5600a2d74d9c68e57974597ab2684...
https://github.com/discourse/discourse/commit/0b5a27e689925edce9ba9b14110022435d...
https://github.com/discourse/discourse/commit/142f5155ad8e56ddb8012c4e70c69a03de...
https://github.com/discourse/discourse/pull/42882
https://github.com/discourse/discourse/security/advisories/GHSA-6pwj-wgg8-4rjc
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