CVE-2024-39274 Malicious remote can add users to arbitrary teams and channels

What is CVE-2024-39274?

CVE-2024-39274 is a high-severity missing authorization vulnerability in Mattermost Mattermost, published on 1 Aug 2024. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to properly validate that the channel that comes from the sync message is a shared channel, when shared channels are enabled, which allows a malicious remote to add users to arbitrary teams and channels

Weakness: CWE-284

Which versions are affected by CVE-2024-39274?

12 open source packages ship an affected version, including github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost-server and github.com/mattermost/mattermost-server/v5. It affects 1 product.

Products include Mattermost Mattermost.

How do I fix CVE-2024-39274?

Upgrade github.com/mattermost/mattermost/server/v8 to a fixed version for your release line: 9.5.7, 9.7.6, 9.8.2 or 9.9.1.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2024-39274 being exploited?

There is no known exploitation of CVE-2024-39274 in the wild and no public exploit code.

Other vulnerabilities in Mattermost Mattermost

• CVE-2019-20851 Path traversal in n/a Critical 9.1
• CVE-2024-39777 Malicious remote can invite itself to an arbitrary local channel High 8.7
• CVE-2024-39830 Timing attack during remote cluster token comparison when shared channels are enabled High 8.1
• CVE-2023-3615 Lack of server certificate validation in websockets connection High 8.1
• CVE-2020-13891 Information disclosure in n/a High 7.5

All Mattermost Mattermost vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-cmc8-222c-vqp9, GO-2024-3028.