| Summary | Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels by pre-registering a user account with a predictable plugin bot username.. Mattermost Advisory ID: MMSA-2026-00649 |
|---|---|
| Publication Date | June 13, 2026, 2:16 a.m. |
| Registration Date | June 13, 2026, 4:18 a.m. |
| Last Update | June 13, 2026, 2:16 a.m. |
| CVSS3.1 : MEDIUM | |
| スコア | 5.3 |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N |
| 攻撃元区分(AV) | ネットワーク |
| 攻撃条件の複雑さ(AC) | 高 |
| 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) | 変更なし |
| 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 |