CVE-2023-5969 Denial of Service via Link Preview in /api/v4/redirect_location

What is CVE-2023-5969?

CVE-2023-5969 is a medium-severity denial of service vulnerability in Mattermost Mattermost, published on 6 Nov 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Mattermost fails to properly sanitize the request to /api/v4/redirect_location allowing an attacker, sending a specially crafted request to /api/v4/redirect_location, to fill up the memory due to caching large items.

Weakness: CWE-400

Which versions are affected by CVE-2023-5969?

8 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-2023-5969?

Upgrade github.com/mattermost/mattermost/server/v8 to a fixed version for your release line: 8.0.4, 8.1.3 or 9.0.1.

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-2023-5969 being exploited?

There is no known exploitation of CVE-2023-5969 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-w496-f5qq-m58j.