Description
Mattermost versions 10.11.x <= 10.11.4 fail to validate redirect URLs on the /error page, which allows an attacker to redirect a victim to a malicious site via a crafted link opened in a new tab.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mattermost | Mattermost | 10.11.0 – ≤ 10.11.4 | 11.1.0 |
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 | 0.0.20260114T191543-150000.1.137.1 | SUSE-SU-2026:0142-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/mattermost/mattermost | >= 10.11.0-rc1, < 10.11.5-0.20251016131338-dad6bd7a1509 | 10.11.5-0.20251016131338-dad6bd7a1509 | GHSA-q66g-q98c-q454 |
| Go | github.com/mattermost/mattermost | >= 11.0.0-alpha.1, < 11.1.0 | 11.1.0 | GHSA-q66g-q98c-q454 |
| Go | github.com/mattermost/mattermost | >= 10.11.0-rc1+incompatible, < 11.1.0+incompatible | 11.1.0+incompatible | GO-2025-4248 |
| Go | github.com/mattermost/mattermost-server | all versions | — | GO-2025-4248 |
| Go | github.com/mattermost/mattermost-server/v5 | all versions | — | GO-2025-4248 |
| Go | github.com/mattermost/mattermost-server/v6 | all versions | — | GO-2025-4248 |
| Go | github.com/mattermost/mattermost/server/v8 | >= 8.0.0-20250721062209-4952acea88ce, < 8.0.0-20251016131338-dad6bd7a1509 | 8.0.0-20251016131338-dad6bd7a1509 | GHSA-q66g-q98c-q454 |
Advisories 2
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- SUSE-SU-2026:0142-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Mar 23, 2026