Description
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to properly validate cache keys for link metadata which allows authenticated users to access unauthorized posts and poison link previews via hash collision attacks on FNV-1 hashing
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mattermost | Mattermost | 10.8.0 – ≤ 10.8.3, 10.5.0 – ≤ 10.5.8, 9.11.0 – ≤ 9.11.17, 10.10.0 – ≤ 10.10.1, 10.9.0 – ≤ 10.9.3 | 10.11.0 |
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.
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP6 | govulncheck-vulndb | 0.0.20250918T182144-150000.1.107.1 | SUSE-SU-2025:03289-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | govulncheck-vulndb | 0.0.20250917T170349-1.1 | openSUSE-SU-2025:15564-1 |
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
| openSUSE Leap 15.6 | govulncheck-vulndb | 0.0.20250918T182144-150000.1.107.1 | SUSE-SU-2025:03289-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | >= 10.8.0, < 10.8.4 | 10.8.4 | GHSA-9p92-x77w-9fw2 |
| Go | github.com/mattermost/mattermost-server | >= 10.5.0, < 10.5.9 | 10.5.9 | GHSA-9p92-x77w-9fw2 |
| Go | github.com/mattermost/mattermost-server | >= 9.11.0, < 9.11.18 | 9.11.18 | GHSA-9p92-x77w-9fw2 |
| Go | github.com/mattermost/mattermost-server | >= 10.10.0, < 10.10.2 | 10.10.2 | GHSA-9p92-x77w-9fw2 |
| Go | github.com/mattermost/mattermost-server | >= 10.9.0, < 10.9.4 | 10.9.4 | GHSA-9p92-x77w-9fw2 |
| Go | github.com/mattermost/mattermost-server | >= 9.11.0+incompatible, < 9.11.18+incompatible · >= 10.5.0+incompatible, < 10.5.9+incompatible · >= 10.8.0+incompatible, < 10.8.4+incompatible · >= 10.9.0+incompatible, < 10.9.4+incompatible · >= 10.10.0+incompatible, < 10.10.2+incompatible | 9.11.18+incompatible, 10.5.9+incompatible, 10.8.4+incompatible, 10.9.4+incompatible, 10.10.2+incompatible | GO-2025-3959 |
| Go | github.com/mattermost/mattermost-server/v5 | all versions | — | GO-2025-3959 |
| Go | github.com/mattermost/mattermost-server/v6 | all versions | — | GO-2025-3959 |
| Go | github.com/mattermost/mattermost/server/v8 | < 8.0.0-20250718075842-cd87e5c87737 | 8.0.0-20250718075842-cd87e5c87737 | GHSA-9p92-x77w-9fw2 |
Advisories 4
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- openSUSE-SU-2025:15564-1 govulncheck-vulndb-0.0.20250917T170349-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:03289-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2025-1856 Mattermost Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 22, 2025