CVE-2026-6334

low

Published 2026-05-18 · Modified 2026-05-18

CVSS v3

3.1

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N

CVSS v2

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VIR risk

3.1

Description

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

Predictions

Exploit likelihood

42%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No vendor mitigations ingested yet for this CVE. The mitigation-content worker queues fetches as references arrive — check back in a few minutes, or see the references list below.

References

https://mattermost.com/security-updates

CWEs

CWE-305

Verify integrity in audit chain (admin only). AS-IS.