CVE Explorer
CVE-2026-4274
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
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"defaultStatus":"unaffected","product":"Mattermost","vendor":"Mattermost","versions":[{"lessThanOrEqual":"11.2.2","status":"affected","version":"11.2.0","versionType":"semver"},{"lessThanOrEqual":"10.11.10","status":"affected","version":"10.11.0","versionType":"semver"},{"lessThanOrEqual":"11.4.0","status":"affected","version":"11.4.0","versionType":"semver"},{"lessThanOrEqual":"11.3.1","status":"affected","version":"11.3.0","versionType":"semver"},{"status":"unaffected","version":"11.5.0"},{"status":"unaffected","version":"11.2.3"},{"status":"unaffected","version":"10.11.11"},{"status":"unaf…
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:00b7058fd905966bc2d12dd159da211ff0cdc49f1c2a6645064f8dd64ab88680 · sha256:cf2468fdc0cc0f00… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.4,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:00b7058fd905966bc2d12dd159da211ff0cdc49f1c2a6645064f8dd64ab88680 · sha256:cf2468fdc0cc0f00… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-863","description":"CWE-863: Incorrect Authorization","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:00b7058fd905966bc2d12dd159da211ff0cdc49f1c2a6645064f8dd64ab88680 · sha256:cf2468fdc0cc0f00… · /containers/cna/problemTypes/0/descriptions/0
Source references
1 source assertion{"name":"MMSA-2026-00574","tags":["vendor-advisory"],"url":"https://mattermost.com/security-updates"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:00b7058fd905966bc2d12dd159da211ff0cdc49f1c2a6645064f8dd64ab88680 · sha256:cf2468fdc0cc0f00… · /containers/cna/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.