CVE-2026-22880

Mobile SSO authentication flow allows credential theft via malicious server

CVSS 6.1 MEDIUMEPSS 0.1%CWE-352

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.1EPSS 0.1%KEV nãoPoC —Nuclei —Metasploit —Patch referenciado

Lifecycle

21 May 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

Mattermost Mobile Apps versions <=2.37 11.4 2.0.37 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to properly validate the SSO authentication callback origin which allows an attacker controlling a malicious Mattermost server to steal user credentials for a legitimate Mattermost server via relaying the SSO code exchange flow through the mobile application. Mattermost Advisory ID: MMSA-2025-00564

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

Affected products

Mattermost · Mattermost

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References

https://mattermost.com/security-updates