CVSS 3.1
4.3 mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NCVE-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 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
Severity
- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 7% of CVEs (scores of 2026-10-31)
- CWE
- CWE-200
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mattermost:mattermost_server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-rp4v-qc77-phm4 | Go | github.com/mattermost/mattermost-server | >=11.6.0 <11.6.1 | 11.6.1 |
| GHSA-rp4v-qc77-phm4 | Go | github.com/mattermost/mattermost-server | >=11.5.0 <11.5.5 | 11.5.5 |
| GHSA-rp4v-qc77-phm4 | Go | github.com/mattermost/mattermost-server | >=10.11.0 <10.11.17 | 10.11.17 |
| GHSA-rp4v-qc77-phm4 | Go | github.com/mattermost/mattermost/server/v8 | >=8.0.0-20250731163400-5b955468ea1e <8.0.0-20260504071740-9408b98025d7 | 8.0.0-20260504071740-9408b98025d7 |
| GO-2026-6286 | Go | github.com/mattermost/mattermost-server | >=10.11.0+incompatible <10.11.17+incompatible >=11.5.0+incompatible <11.5.5+incompatible >=11.6.0+incompatible <11.6.1+incompatible | 10.11.17+incompatible, 11.5.5+incompatible, 11.6.1+incompatible |
| GO-2026-6286 | Go | github.com/mattermost/mattermost-server/v5 | all versions | no fix published |
| GO-2026-6286 | Go | github.com/mattermost/mattermost-server/v6 | all versions | no fix published |
| GO-2026-6286 | Go | github.com/mattermost/mattermost/server/v8 | >=8.0.0-20250731163400-5b955468ea1e <8.0.0-20260504071740-9408b98025d7 | 8.0.0-20260504071740-9408b98025d7 |