Description
An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2. It allows attackers to cause a denial of service (channel invisibility) via a misformatted post.
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 | < 4.1.2-0.20171013141717-ee57a5829ab1 | 4.1.2-0.20171013141717-ee57a5829ab1 | GHSA-x6mw-hf2j-vqpc |
| Go | github.com/mattermost/mattermost-server | >= 4.2.0, < 4.2.1-0.20171013140502-b3e4b0ac9168 | 4.2.1-0.20171013140502-b3e4b0ac9168 | GHSA-x6mw-hf2j-vqpc |
| Go | github.com/mattermost/mattermost-server | >= 4.3.0-rc1, < 4.3.0 | 4.3.0 | GHSA-x6mw-hf2j-vqpc |
| Go | github.com/mattermost/mattermost-server | < 4.1.2-0.20171013141717-ee57a5829ab1+incompatible · >= 4.2.0+incompatible, < 4.2.1-0.20171013140502-b3e4b0ac9168+incompatible · >= 4.3.0-rc1+incompatible, < 4.3.0+incompatible | 4.1.2-0.20171013141717-ee57a5829ab1+incompatible, 4.2.1-0.20171013140502-b3e4b0ac9168+incompatible, 4.3.0+incompatible | GO-2026-4282 |
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