What is CVE-2026-9602?

CVE-2026-9602 is a medium-severity vulnerability in Mattermost, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2026-07-17.

How severe is CVE-2026-9602?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Resource exhaustion in Mattermost

CVE-2026-9602

Mattermost Desktop App versions <=6.2 6.0.2 5.6.13.0 fail to validate payloads sent from the Mattermost Web App to the Desktop App which allows a malicious server owner to crash the Mattermost Desktop App via changing the payload of a meth…

Vulnerability class: DoS (Denial of Service)

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Mattermost — versions 0, 6.3.0, 6.2.1.0

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

responsibledisclosure@mattermost.com (vendor-advisory)

Frequently asked questions

What is CVE-2026-9602?: CVE-2026-9602 is a medium-severity vulnerability in Mattermost, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2026-07-17.
How severe is CVE-2026-9602?: Medium severity. CVSS v3 base score is 6.5 out of 10.