CVE-2026-22880
Mobile SSO authentication flow allows credential theft via malicious server
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Mobile SSO authentication flow allows credential theft via malicious server
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
- Record
CVE-2026-22880- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N - Weakness
- CWE-352
- Updated
- 2026-11-02
EUVDEUVD-2026-31250
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
- Record
EUVD-2026-31250- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-j628-rc2h-qj7g
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...
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
- Record
GHSA-j628-rc2h-qj7g- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N - Weakness
- CWE-352
- Updated
- 2026-11-02
NVD
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
- Record
CVE-2026-22880- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N - Weakness
- CWE-352
- Updated
- 2026-11-02
OSV
Mobile SSO authentication flow allows credential theft via malicious server
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
- Record
CVE-2026-22880- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N - Weakness
- CWE-352
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-22880 is a medium vulnerability (CVSS 6.1) in Mattermost, published May 21, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.12%, the 1st percentile. No source names a fixed version.