CVE-2026-4339
| Summary |
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
|
| Publication Date |
June 27, 2026, 12:16 a.m. |
| Registration Date |
June 27, 2026, 4:33 a.m. |
| Last Update |
June 27, 2026, 1:16 a.m. |
|
CVSS3.1 : MEDIUM
|
| スコア |
6.5
|
| Vector |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N |
| 攻撃元区分(AV) |
ローカル |
| 攻撃条件の複雑さ(AC) |
低 |
| 攻撃に必要な特権レベル(PR) |
低 |
| 利用者の関与(UI) |
不要 |
| 影響の想定範囲(S) |
変更あり |
| 機密性への影響(C) |
高 |
| 完全性への影響(I) |
なし |
| 可用性への影響(A) |
なし |
Related information, measures and tools
Common Vulnerabilities List