CVE-2026-3590

Race Condition in Guest Magic Link Authentication Allows Token Reuse

CVSS 6.5 MEDIUMEPSS 0.1%CWE-367

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.5EPSS 0.1%KEV nãoPoC —Nuclei —Metasploit —Patch referenciado

Lifecycle

15 Apr 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624

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

Affected products

Mattermost · Mattermost

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References

https://mattermost.com/security-updates