CVE-2026-6334
OAuth authorization code client binding not enforced during token redemption in Mattermost
CVSS Score
3.1
EPSS Score
0.0%
EPSS Percentile
7th
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to enforce client identity binding during the OAuth authorization code redemption flow which allows an authenticated OAuth client to redeem authorization codes issued to a different client via a crafted token exchange request.. Mattermost Advisory ID: MMSA-2026-00570
| CWE | CWE-305 |
| Vendor | mattermost |
| Product | mattermost |
| Published | May 18, 2026 |
| Last Updated | May 18, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
High
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
Mattermost / Mattermost
11.5.0 ≤ 11.5.1 10.11.0 ≤ 10.11.13
Credits
Dylan Haussermann