How severe is CVE-2025-55070?

CVE-2025-55070 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-55070 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-55070?

CVE-2025-55070 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-55070?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-55070 have an EU (EUVD) identifier?

Yes. CVE-2025-55070 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-186556.

When was CVE-2025-55070 published?

CVE-2025-55070 was published on 2025-11-14 and last updated on 2026-06-17.

CVE-2025-55070

Q: What is 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

CVE-2025-55070 is a medium-severity vulnerability in Mattermost Mattermost Server with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-186556
Weakness: CWE-306
Affected product: Mattermost Mattermost Server
Published: 2025-11-14
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is 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
How severe is CVE-2025-55070?: CVE-2025-55070 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-55070 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-55070?: CVE-2025-55070 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-55070?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-55070 have an EU (EUVD) identifier?: Yes. CVE-2025-55070 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-186556.
When was CVE-2025-55070 published?: CVE-2025-55070 was published on 2025-11-14 and last updated on 2026-06-17.

References

https://mattermost.com/security-updates

Affected products (1)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

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