CVE-2026-96259
Mattermost server-side request forgery via OAuth endpoints configurable by a System Administrator
CVSS Score
5.5
EPSS Score
0.0%
EPSS Percentile
0th
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776
| CWE | CWE-918 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Sep 22, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
Mattermost / Mattermost
11.9.0 ≤ 11.9.1 11.8.0 ≤ 11.8.5 11.7.0 ≤ 11.7.10 11.10.0 ≤ 11.10.1
Credits
n1nj4sec