Mattermost fails to scope role_updated websocket events to authorized team and channel members
Published Jun 12, 2026
4.3
MEDIUMCVSS 3.1
EPSS 0.30%
Description
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 products
-
- Version 10.11.0StatusaffectedConstraints<=10.11.15
- Version 10.11.0StatusaffectedConstraints<=10.11.16
- Version 11.5.0StatusaffectedConstraints<=11.5.4
- Version 11.6.0StatusaffectedConstraints<=11.6.1
- Version 10.11.16StatusunaffectedConstraints-
- Version 10.11.17StatusunaffectedConstraints-
- Version 11.5.5StatusunaffectedConstraints-
- Version 11.6.2StatusunaffectedConstraints-
- Version 11.7.0StatusunaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mattermost | Mattermost | unaffected |
|
- ≥ 10.11.0 · < 10.11.17
- ≥ 11.5.0 · < 11.5.5
- ≥ 11.6.0 · < 11.6.2
No data.
No Red Hat product state for this CVE.
github.com/mattermost/mattermost/server/v8
Go
Introduced 8.0.0-20250731163400-5b955468ea1e Fixed 8.0.0-20260504071740-9408b98025d7github.com/mattermost/mattermost-server/v5
Go
Introduced 0 Fixed not fixedgithub.com/mattermost/mattermost-server/v6
Go
Introduced 0 Fixed not fixedgithub.com/mattermost/mattermost-server
Go
Introduced 11.5.0+incompatible Fixed 11.5.5+incompatiblegithub.com/mattermost/mattermost-server
Go
Introduced 11.6.0+incompatible Fixed 11.6.1+incompatiblegithub.com/mattermost/mattermost-server
Go
Introduced 10.11.0+incompatible Fixed 10.11.17+incompatible
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20250731163400-5b955468ea1e | 8.0.0-20260504071740-9408b98025d7 |
| Go | github.com/mattermost/mattermost-server/v5 | 0 | not fixed |
| Go | github.com/mattermost/mattermost-server/v6 | 0 | not fixed |
| Go | github.com/mattermost/mattermost-server | 11.5.0+incompatible | 11.5.5+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.6.0+incompatible | 11.6.1+incompatible |
| Go | github.com/mattermost/mattermost-server | 10.11.0+incompatible | 10.11.17+incompatible |
Remediation
Vendor solution
Update Mattermost to versions 11.7.0, 11.6.2, 11.5.5, 10.11.16, 10.11.17 or higher.
References (16)
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-36498 Advisory
- https://github.com/advisories/GHSA-rp4v-qc77-phm4 Advisory
- 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/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/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
- https://mattermost.com/security-updates vendor-advisoryVendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-3433
Change history (0)
No recorded changes yet.