How severe is CVE-2025-6227?

CVE-2025-6227 has a CVSS 3.x base score of 2.2, rated low severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2025-6227 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-6227?

CVE-2025-6227 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-6227?

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

Does CVE-2025-6227 have an EU (EUVD) identifier?

Yes. CVE-2025-6227 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21876.

When was CVE-2025-6227 published?

CVE-2025-6227 was published on 2025-07-18 and last updated on 2026-06-17.

CVE-2025-6227

CVE-2025-6227 is a low-severity vulnerability in Mattermost Mattermost Server with a CVSS 3.x base score of 2.2. 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-522.

Key facts

Severity: Low (CVSS 3.x base score 2.2)
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-21876
Weakness: CWE-522
Affected product: Mattermost Mattermost Server
Published: 2025-07-18
Last modified: 2026-06-17

Description

Mattermost versions 10.5.x <= 10.5.7, 9.11.x <= 9.11.16 fail to negotiate a new token when accepting the invite which allows a user that intercepts both invite and password to send synchronization payloads to the server that originally created the invite via the REST API.

Frequently asked questions

What is CVE-2025-6227?: Mattermost versions 10.5.x <= 10.5.7, 9.11.x <= 9.11.16 fail to negotiate a new token when accepting the invite which allows a user that intercepts both invite and password to send synchronization payloads to the server that originally created the invite via the REST API.
How severe is CVE-2025-6227?: CVE-2025-6227 has a CVSS 3.x base score of 2.2, rated low severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2025-6227 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-6227?: CVE-2025-6227 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-6227?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-6227 have an EU (EUVD) identifier?: Yes. CVE-2025-6227 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21876.
When was CVE-2025-6227 published?: CVE-2025-6227 was published on 2025-07-18 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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