High severity · published Nov 14, 2025
CVE-2025-55070
Lack of MFA enforcement in WebSocket connections
7.5
CVSS
0.3%
EPSS
No
On KEV
Description
Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
<11 through <11 · source: vendor
MS
Mattermost Server · Mattermost
before 11.0.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-55070
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-55070
Vendor Advisory
https://mattermost.com/security-updates
More from Mattermost
9.9
CVE-2026-4858
Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
9.9
CVE-2025-12421
Account Takeover via Code Exchange Endpoint
9.9
CVE-2025-12419
Account takeover on OAuth/OpenID-enabled servers
9.6
CVE-2024-39777
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to disallow unsolicited invites to expose access to local channels, when shared channels…
9.3
CVE-2026-12985
Mattermost DCR redirect URI allowlist bypass via improper URL component validation