Home/CVE/Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the A
CVE

CVE-2025-11777

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the A

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata and channel membership information from other teams via the API endpoint.

LOW · CVSS 3.1 EPSS 0.00027
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-863Incorrect Authorization
▤

Affected Products & Versions

2
mattermost server>= 10.5.0 and < 10.5.12
mattermost server>= 10.11.0 and < 10.11.4
▤

Affected Packages

6
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Go github.com/mattermost/mattermost LOW fixed in 5.3.2-0.20250905150616-ba86dfc5876b
Go github.com/mattermost/mattermost-server LOW fixed in 10.11.4
Go github.com/mattermost/mattermost-server/v5 LOW fixed in 5.3.2-0.20250905150616-ba86dfc5876b
Go github.com/mattermost/mattermost-server/v6 LOW fixed in 5.3.2-0.20250905150616-ba86dfc5876b
Go github.com/mattermost/mattermost/server/v8 LOW fixed in 8.0.0-20250905150616-ba86dfc5876b
Go github.com/mattermost/mattermost/v5
▣

Scoring & Timeline

3.1
LOW · CVSS v3.1 · responsibledisclosure@mattermost.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD13 Nov 2025 · 06:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://mattermost.com/security-updatesVendor Advisory
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