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Vulnerabilities

Vulnerability · CVE-2025-55070

Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events

Published Nov 14, 2025 · catalog updated Nov 14, 2025 · Mattermost Mattermost

Last checked Oct 25, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-55070. EPSS is 0.32%. Act only if a listed version of Mattermost Mattermost is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.32%
Remediation
Version ranges on file
Affected products
vendor Mattermost Mattermost <11 ≤<11

Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Mattermost Mattermost <11 ≤<11<11 ≤<11

How to fix CVE-2025-55070

  • Upgrade

    CVE-2025-55070 lists a fix boundary at 11. Compare the installed build with that boundary before you change production.

  • Version check

    Affected <11 ≤<11

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-55070. EPSS is 0.32%. Act only if a listed version of Mattermost Mattermost is installed.

Which versions are affected?

Compare what you have installed with Mattermost Mattermost <11 ≤<11 <11 ≤<11. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.32%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 14, 2025 · EUVD

    Detected

    Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events

  2. Nov 14, 2025 · EUVD

    Updated

    Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events

Sources

  • CVE.orgVulnerability recordCVE-2025-55070

    Official CVE identifier

    cve.org
  • EUVDVulnerability recordEUVD-2025-186556

    Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 25, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 25, 2026
  • EUVDOct 25, 2026