> CVE-2026-54256 [MEDIUM]

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PUBLISHED
2026-08-26 18:16
MODIFIED
2026-08-26 18:16
CVSS_SCORE V3
5.4
EPSS (Prob. Exploit)
0.24%
Top 86.0%
DATA SOURCES:
NVD 🔗 2026-08-26 CWE MITRE 🔗 2026-09-01 FIRST EPSS 🔗 2026-10-18 GITHUB 🔗 2026-10-29 OSV 🔗 2026-10-26

> DESCRIPTION

Winter CMS is a content management system built on the Laravel PHP framework. In versions up to and including 1.2.12, the backend FileUpload form widget trusted an attacker-controlled file_id POST parameter when resolving the attachment it operates on, allowing an authenticated backend user to read and modify attachment records belonging to other users or records. The widget's getFileRecord() lookup resolved the posted id against the global system_files table without verifying that the file belonged to the widget's own relation, parent record, or deferred-binding session. Because all attachments share a single File model and table and attachment ids are sequential integers that are easily enumerated, a user reaching any form with a fileupload field, including the built-in My Account avatar field that requires no specific permission, could target arbitrary attachments to modify their title and description via onSaveAttachmentConfig and change their sort order via onSortAttachments, which passed posted ids straight to an unscoped update. CSRF tokens remain enforced, so exploitation requires a valid authenticated backend session with any level of access. This issue is fixed in version 1.2.13.

> 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:L/UI:N/S:U/C:L/I:L/A:N
EXPLOITABILITY
2.8
IMPACT
2.5

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/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
Low (L)
Authentifié avec compte utilisateur basique
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
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-284 CWE-639

> CWE DETAILED DESCRIPTIONS

CWE-284: Improper Access Control - The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. | CWE-639: Authorization Bypass Through User-Controlled Key - The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

> GITHUB SECURITY ADVISORY

GHSA-3277-h8g9-qj5f MODERATE

Winter: Authenticated IDOR in backend FileUpload widget allows cross-user access to attachment metadata

AFFECTED PACKAGES:
COMPOSER / winter/wn-backend-module
<= 1.2.12
Fixed in: 1.2.13

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Winter: Authenticated IDOR in backend FileUpload widget allows cross-user access to attachment metadata

AFFECTED PACKAGES:
Unknown / Unknown
138 versions affected
ALIASES:
GHSA-3277-h8g9-qj5f

> HISTORIQUE DES MODIFICATIONS

Première apparition
26/08/2026 18:16
Source: NVD
📊 ENRICHISSEMENT 01/09/2026 06:02
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-284: Improper Access Control - The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. | CWE-639: Authorization Bypass Through User-Controlled Key -...
Total des modifications: 1 Dernière mise à jour: 1 month ago

> REFERENCES

https://github.com/wintercms/winter/commit/9cb0ae5f9d837db141ab111c6a7de8eed9603...
https://github.com/wintercms/winter/security/advisories/GHSA-3277-h8g9-qj5f
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