CyberRota Analysis
This is a medium severity vulnerability with a CVSS score of 6.5. See the original NVD description below for full technical details.
CVE
CVE-2026-4339
Severity
MEDIUM
CVSS
6.5
EPSS
0.10%
Original NVD 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
Related CVEs
Other vulnerabilities affecting the same vendor(s)