No advisories yet.
Solution
Update Mattermost to versions 11.7.0, 10.11.19, 11.6.4, 11.5.7 or higher.
Workaround
No workaround given by the vendor.
| Link | Providers |
|---|---|
| https://mattermost.com/security-updates |
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Fri, 26 Jun 2026 19:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Mattermost
Mattermost mattermost |
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| Vendors & Products |
Mattermost
Mattermost mattermost |
Fri, 26 Jun 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Fri, 26 Jun 2026 15:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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 | |
| Title | SSRF via unvalidated attachment URLs in Mattermost Agents plugin MCP server | |
| Weaknesses | CWE-918 | |
| References |
| |
| Metrics |
cvssV3_1
|
Projects
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Status: PUBLISHED
Assigner: Mattermost
Published:
Updated: 2026-06-26T15:40:33.300Z
Reserved: 2026-03-17T14:57:10.575Z
Link: CVE-2026-4339
Updated: 2026-06-26T15:40:28.917Z
No data.
No data.
OpenCVE Enrichment
Updated: 2026-06-26T19:00:04Z