Description
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to sanitize sensitive data in WebSocket messages which allows authenticated users to exfiltrate password hashes and MFA secrets via profile nickname updates or email verification events. Mattermost Advisory ID: MMSA-2025-00560
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mattermost | Mattermost | 11.1.0 – ≤ 11.1.2, 10.11.0 – ≤ 10.11.9, 11.2.0 – ≤ 11.2.1 | 11.3.0 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
| openSUSE Leap 15.6 | govulncheck-vulndb | 0.0.20260226T182644-150000.1.149.1 | SUSE-SU-2026:0757-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | >= 11.1.0 | — | GHSA-pp9j-pf5c-659x |
| Go | github.com/mattermost/mattermost-server | >= 10.11.0 | — | GHSA-pp9j-pf5c-659x |
| Go | github.com/mattermost/mattermost-server | >= 11.2.0 | — | GHSA-pp9j-pf5c-659x |
| Go | github.com/mattermost/mattermost-server | < 5.3.2-0.20251210191531-cd17b61de41b | 5.3.2-0.20251210191531-cd17b61de41b | GHSA-pp9j-pf5c-659x |
| Go | github.com/mattermost/mattermost-server | all versions | — | GO-2026-4524 |
| Go | github.com/mattermost/mattermost-server | >= 10.11.0+incompatible | — | GO-2026-4524 |
| Go | github.com/mattermost/mattermost-server | >= 11.1.0+incompatible | — | GO-2026-4524 |
| Go | github.com/mattermost/mattermost-server | >= 11.2.0+incompatible | — | GO-2026-4524 |
| Go | github.com/mattermost/mattermost-server/v5 | all versions | — | GO-2026-4524 |
| Go | github.com/mattermost/mattermost-server/v6 | all versions | — | GO-2026-4524 |
| Go | github.com/mattermost/mattermost/server/v8 | < 8.0.0-20251210191531-cd17b61de41b | 8.0.0-20251210191531-cd17b61de41b | GHSA-pp9j-pf5c-659x |
Advisories 2
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- SUSE-SU-2026:0757-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Mar 4, 2026
References
- MMSA-2025-00560 vendor-advisory