CVE-2023-5196 DoS via Channel Notification Properties

What is CVE-2023-5196?

CVE-2023-5196 is a medium-severity denial of service vulnerability in Mattermost Mattermost, published on 29 Sep 2023. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Mattermost fails to enforce character limits in all possible notification props allowing an attacker to send a really long value for a notification_prop resulting in the server consuming an abnormal quantity of computing resources and possibly becoming temporarily unavailable for its users.

Weakness: CWE-400

Which versions are affected by CVE-2023-5196?

6 open source packages ship an affected version, including github.com/mattermost/mattermost/server/v8 and github.com/mattermost/mattermost-server/v6. It affects 1 product.

Products include Mattermost Mattermost.

How do I fix CVE-2023-5196?

Upgrade github.com/mattermost/mattermost/server/v8 to a fixed version for your release line: 8.0.2 or 8.1.1.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2023-5196 being exploited?

There is no known exploitation of CVE-2023-5196 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-2024-39274 Malicious remote can add users to arbitrary teams and channels High 8.7
• 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

All Mattermost Mattermost vulnerabilities

Sources

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

Also known as GHSA-33r7-wjfc-7w98.