medium4.3
CVE-2026-3433
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to restrict role_updated websocket event broadcasts to me…
Impact
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to restrict role_updated websocket event broadcasts to members of the affected team or channel which allows an authenticated attacker with guest-level access to observe permission scheme change notifications for private teams they are not a member of via the websocket connection.. Mattermost Advisory ID: MMSA-2026-00616
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/mattermost/mattermost-server | = 11.6.0 | 11.6.1 |
| go | github.com/mattermost/mattermost/server/v8 | >= 8.0.0-20250731163400-5b955468ea1e, < 8.0.0-20260504071740-9408b98025d7 | 8.0.0-20260504071740-9408b98025d7 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Mattermost | Mattermost Server | from 10.11.0 before 10.11.17 from 11.5.0 before 11.5.5 from 11.6.0 before 11.6.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-rp4v-qc77-phm4
- https://nvd.nist.gov/vuln/detail/CVE-2026-3433
- https://mattermost.com/security-updates
- https://github.com/mattermost/mattermost/pull/35497
- https://github.com/mattermost/mattermost/pull/36256
- https://github.com/mattermost/mattermost/pull/36257
- https://github.com/mattermost/mattermost/pull/36341
- https://github.com/mattermost/mattermost/commit/0a0ab0d54d899d308bd1352cc577036917500318
- https://github.com/mattermost/mattermost/commit/7425c6817bf244f976c729f8a73cecac8039a1e1
- https://github.com/mattermost/mattermost/commit/9408b98025d7364d7dfe7cdb28fcd109b1b595a6
- https://github.com/mattermost/mattermost/commit/a30a331a29b9766d46716d4252056d7b74e66da0
- https://github.com/mattermost/mattermost/releases/tag/v10.11.16
- https://github.com/mattermost/mattermost/releases/tag/v11.5.5
- https://github.com/mattermost/mattermost/releases/tag/v11.6.2
- https://github.com/mattermost/mattermost/releases/tag/v11.7.0