Description
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate that the RefreshedToken differs from the original invite token during remote cluster invite confirmation which allows an authenticated attacker to bypass token rotation and reuse the original invite token via sending a crafted invite confirmation with a RefreshedToken matching the original token. Mattermost Advisory ID: MMSA-2026-00575
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mattermost | Mattermost | 11.5.0 – ≤ 11.5.1, 10.11.0 – ≤ 10.11.13 | 11.6.0 |
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 | < 5.3.2-0.20260313190740-742e0be95074 | 5.3.2-0.20260313190740-742e0be95074 | GHSA-hqpj-f3jh-29vx |
| Go | github.com/mattermost/mattermost-server | >= 10.11.0+incompatible, < 10.11.14+incompatible · >= 11.5.0+incompatible, < 11.5.2+incompatible | 10.11.14+incompatible, 11.5.2+incompatible | GO-2026-5432 |
| Go | github.com/mattermost/mattermost-server/v5 | all versions | — | GO-2026-5432 |
| Go | github.com/mattermost/mattermost-server/v6 | all versions | — | GO-2026-5432 |
| Go | github.com/mattermost/mattermost/server/v8 | >= 11.5.0, < 11.5.2 | 11.5.2 | GHSA-hqpj-f3jh-29vx |
| Go | github.com/mattermost/mattermost/server/v8 | >= 10.11.0, < 10.11.14 | 10.11.14 | GHSA-hqpj-f3jh-29vx |
| Go | github.com/mattermost/mattermost/server/v8 | < 8.0.0-20260313190740-742e0be95074 | 8.0.0-20260313190740-742e0be95074 | GHSA-hqpj-f3jh-29vx |
Advisories 1
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
References
- MMSA-2026-00575 vendor-advisory