CVE-2026-4339

6.5 Moyenne

Publiée le 26/06/2026 à 17:16 · Modifiée le 29/06/2026 à 21:26 · Analysée par le NVD · Source : responsibledisclosure@mattermost.com

Description

Mattermost versions 10.11.x <= 10.11.18, 11.6.x <= 11.6.3, 11.5.x <= 11.5.6 fail to validate attachment URLs against internal or private IP ranges in the Mattermost Agents plugin MCP server which allows an attacker with access to the MCP server in stdio mode to perform server-side request forgery (SSRF) and exfiltrate data from internal network services via supplying internal URLs as file attachments in post creation requests.. Mattermost Advisory ID: MMSA-2026-00635

Traduire en français

Produits concernés

Mattermost
Mattermost mattermost server

Scores CVSS

Version	Score	Source	Vecteur
3.1	6.5 Moyenne	responsibledisclosure@mattermost.com	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N`

Faiblesses (CWE)

CWE-918

Références

https://mattermost.com/security-updates Vendor Advisory

Ailleurs

NVD
CVE.org
CIRCL Vulnerability-Lookup
CERT-FR
GitHub Advisories