How severe is CVE-2025-11777?

CVE-2025-11777 has a CVSS 3.x base score of 3.1, rated low severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2025-11777 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-11777?

CVE-2025-11777 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-11777?

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

Does CVE-2025-11777 have an EU (EUVD) identifier?

Yes. CVE-2025-11777 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-175343.

When was CVE-2025-11777 published?

CVE-2025-11777 was published on 2025-11-13 and last updated on 2026-06-17.

CVE-2025-11777

CVE-2025-11777 is a low-severity vulnerability in Mattermost Mattermost Server with a CVSS 3.x base score of 3.1. 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-863.

Key facts

Severity: Low (CVSS 3.x base score 3.1)
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-175343
Weakness: CWE-863
Affected product: Mattermost Mattermost Server
Published: 2025-11-13
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is 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 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
How severe is CVE-2025-11777?: CVE-2025-11777 has a CVSS 3.x base score of 3.1, rated low severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2025-11777 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-11777?: CVE-2025-11777 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-11777?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-11777 have an EU (EUVD) identifier?: Yes. CVE-2025-11777 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-175343.
When was CVE-2025-11777 published?: CVE-2025-11777 was published on 2025-11-13 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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