Medium severity · published May 21, 2026
CVE-2026-22880
Mobile SSO authentication flow allows credential theft via malicious server
6.1
CVSS
0.1%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
None
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 2% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
through 2.0.37; through 11.0.4; through 11.1.3; through 11.3.2; through 10.11.11 · source: vendor
MM
Mattermost Mobile · Mattermost
before 2.37.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-22880
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-22880
Vendor Advisory
https://mattermost.com/security-updates
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