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CVE-2025-27571 Moderate

Mattermost Incorrect Authorization vulnerability

Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to check the "Allow Users to View Archived Channels" configuration when fetching channel metadata of a post from archived channels, which allows authenticated users to access such information when a channel is archived.

Exploit probability 0.3%
Published April 16, 2025
Required by Not available
Last source change February 4, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

45 explicit affected versions

Go github.com/mattermost/mattermost/server/v8
Go github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server/v5
Go github.com/mattermost/mattermost-server/v6
Go github.com/mattermost/mattermost/server/v8

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities CVE-2025-27571

Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to check the "Allow Users to View Archived Channels" configuration when fetching channel metadata of a post from archived channels, which allows authenticated users to access such information when a channel is archived.

View original source
Open Source Vulnerabilities GHSA-h4rr-f37j-4hh7

Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to check the "Allow Users to View Archived Channels" configuration when fetching channel metadata of a post from archived channels, which allows authenticated users to access such information when a channel is archived.

View original source
Open Source Vulnerabilities GO-2025-3619

Mattermost Incorrect Authorization vulnerability in github.com/mattermost/mattermost-server

View original source

05 / REFERENCES

Further evidence