CVE-2026-4274
CVE.org · Published
- Record status
- Published
- Identifier year (not publication year)
- 2026
- Source publication
- Source updated
- Imported by cveboard
- Source snapshot
- cve_2026-10-24_midnight_baseline ·
CNA source text (English)
Insufficient authorization in shared channel membership sync grants team-level access instead of channel-level access
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to restrict team-level access when processing membership sync from a remote cluster, which allows a malicious remote cluster to grant a user access to an entire private team instead of only the shared channel via sending crafted membership sync messages that trigger team membership assignment. Mattermost Advisory ID: MMSA-2026-00574
Scoped product and version facts
Fix information unknown; no fixed version is derived here. Missing information does not prove that no fix exists.
Exploitation unknown; this catalogue does not assess exploitation.
Mattermost
- Vendor
- Mattermost
- Product
- Mattermost
- Platforms
- Unknown
- Default status
unaffected
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| 11.2.0 | affected | semver | Unavailable | 11.2.2 | None listed |
| 10.11.0 | affected | semver | Unavailable | 10.11.10 | None listed |
| 11.4.0 | affected | semver | Unavailable | 11.4.0 | None listed |
| 11.3.0 | affected | semver | Unavailable | 11.3.1 | None listed |
| 11.5.0 | unaffected | Unavailable | Unavailable | Unavailable | None listed |
| 11.2.3 | unaffected | Unavailable | Unavailable | Unavailable | None listed |
| 10.11.11 | unaffected | Unavailable | Unavailable | Unavailable | None listed |
| 11.4.1 | unaffected | Unavailable | Unavailable | Unavailable | None listed |
| 11.3.2 | unaffected | Unavailable | Unavailable | Unavailable | None listed |