Description
An issue was discovered in Mattermost Server before 4.0.0, 3.10.2, and 3.9.2. XSS could occur via a channel header.
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 | < 3.9.2-0.20170714014920-312269ad0bd1 | 3.9.2-0.20170714014920-312269ad0bd1 | GHSA-42x9-rr3c-gr59 |
| Go | github.com/mattermost/mattermost-server | >= 3.10.0, < 3.10.2 | 3.10.2 | GHSA-42x9-rr3c-gr59 |
| Go | github.com/mattermost/mattermost-server | >= 3.10.0+incompatible, < 3.10.2+incompatible | 3.10.2+incompatible | GO-2026-4459 |
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