How severe is CVE-2026-27769?

CVE-2026-27769 has a CVSS 3.x base score of 2.7, rated low severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-27769 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-2026-27769?

CVE-2026-27769 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27769?

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

Does CVE-2026-27769 have an EU (EUVD) identifier?

Yes. CVE-2026-27769 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22873.

When was CVE-2026-27769 published?

CVE-2026-27769 was published on 2026-04-15 and last updated on 2026-06-17.

CVE-2026-27769

CVE-2026-27769 is a low-severity vulnerability in Mattermost Mattermost Server with a CVSS 3.x base score of 2.7. 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-862.

Key facts

Severity: Low (CVSS 3.x base score 2.7)
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-22873
Weakness: CWE-862
Affected product: Mattermost Mattermost Server
Published: 2026-04-15
Last modified: 2026-06-17

Description

Mattermost versions 10.11.x <= 10.11.12 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicious remote server connected using the Conntexted Workspaces feature to change the displayed status of local users via the Connected Workspaces API.. Mattermost Advisory ID: MMSA-2026-00603

Frequently asked questions

What is CVE-2026-27769?: Mattermost versions 10.11.x <= 10.11.12 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicious remote server connected using the Conntexted Workspaces feature to change the displayed status of local users via the Connected Workspaces API.. Mattermost Advisory ID: MMSA-2026-00603
How severe is CVE-2026-27769?: CVE-2026-27769 has a CVSS 3.x base score of 2.7, rated low severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-27769 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-2026-27769?: CVE-2026-27769 affects Mattermost Mattermost Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27769?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-27769 have an EU (EUVD) identifier?: Yes. CVE-2026-27769 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22873.
When was CVE-2026-27769 published?: CVE-2026-27769 was published on 2026-04-15 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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