CVE-2026-4339mediumCWE-918

SSRF via unvalidated attachment URLs in Mattermost Agents plugin MCP server

13Vexday Risk Score

Sin señal de explotación. Ningún artefacto público de explotación conocido hasta ahora.

ssvc Trackcvss 6.5epss 0.1%

probabilidad de explotación

0.1%top 99% de las CVE

explotación observada

noninguna fuente lo reporta

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

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Productos afectados

Mattermost · Mattermost

Referencias

https://mattermost.com/security-updates