- 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
- Source
- responsibledisclosure@mattermost.com
- NVD status
- Analyzed
- Products
- mattermost_server
CVSS 3.1
- Type
- Secondary
- Base score
- 6.5
- Impact score
- 4
- Exploitability score
- 2
- Vector string
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
- Severity
- MEDIUM
- responsibledisclosure@mattermost.com
- CWE-918
- Hype score
- Not currently trending
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