CVE-2026-4339mediumCWE-918

SSRF via unvalidated attachment URLs in Mattermost Agents plugin MCP server

13Vexday Risk Score

Sem sinal de exploração. Nenhum artefato público de exploração conhecido até agora.

ssvc Trackcvss 6.5epss 0.1%

probabilidade de exploração

0.1%top 99% das CVEs

exploração observada

nãonenhuma fonte 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

Produtos afetados

Mattermost · Mattermost

Referências

https://mattermost.com/security-updates