CVE-2024-1402

Mattermost fails to check if a custom emoji reaction exists when sending it to a post and to limit the amount of custom emojis allowed to be added in a post, allowing an attacker sending a huge amount of non-existent custom emojis in a post to crash the mobile app of a user seeing the post. Fetching posts with huge amounts of reactions results in Uncontrolled Resource Consumption.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2024-1402 has a CVSS score of 4.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (8.1.8, 9.2.4, 9.1.5); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2024-1402? CVE-2024-1402 is a medium-severity uncontrolled resource consumption vulnerability in github.com/mattermost/mattermost/server/v8 (go), affecting versions < 8.1.8. It is fixed in 8.1.8, 9.2.4, 9.1.5. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2024-1402? CVE-2024-1402 has a CVSS score of 4.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/mattermost/mattermost/server/v8 are affected by CVE-2024-1402? github.com/mattermost/mattermost/server/v8 (go) versions < 8.1.8 is affected.
4. Is there a fix for CVE-2024-1402? Yes. CVE-2024-1402 is fixed in 8.1.8, 9.2.4, 9.1.5. Upgrade to this version or later.
5. Is CVE-2024-1402 exploitable, and should I be worried? Whether CVE-2024-1402 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2024-1402 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2024-1402?
   • Upgrade github.com/mattermost/mattermost/server/v8 to 8.1.8 or later
   • Upgrade github.com/mattermost/mattermost/server/v8 to 9.2.4 or later
   • Upgrade github.com/mattermost/mattermost/server/v8 to 9.1.5 or later

Other vulnerabilities in github.com/mattermost/mattermost/server/v8