Description
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting existing persistent notifications and archiving the channel.. Mattermost Advisory ID: MMSA-2026-00637
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mattermost | Mattermost | 11.6.0 – ≤ 11.6.0, 11.5.0 – ≤ 11.5.3, 11.4.0 – ≤ 11.4.4, 10.11.0 – ≤ 10.11.14 | 11.7.0 |
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 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | >= 11.6.0, < 11.6.1 | 11.6.1 | GHSA-pg7c-462j-grxv |
| Go | github.com/mattermost/mattermost-server | >= 11.5.0, < 11.5.4 | 11.5.4 | GHSA-pg7c-462j-grxv |
| Go | github.com/mattermost/mattermost-server | >= 11.4.0, < 11.4.5 | 11.4.5 | GHSA-pg7c-462j-grxv |
| Go | github.com/mattermost/mattermost-server | >= 10.11.0, < 10.11.15 | 10.11.15 | GHSA-pg7c-462j-grxv |
| Go | github.com/mattermost/mattermost-server | >= 10.11.0+incompatible, < 10.11.15+incompatible · >= 11.4.0+incompatible, < 11.4.5+incompatible · >= 11.5.0+incompatible, < 11.5.4+incompatible · >= 11.6.0+incompatible, < 11.6.1+incompatible | 10.11.15+incompatible, 11.4.5+incompatible, 11.5.4+incompatible, 11.6.1+incompatible | GO-2026-5820 |
Advisories 1
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
References
- MMSA-2026-00637 vendor-advisory