Payload Validation Flaw in Mattermost Desktop App from Mattermost
CVE-2026-9602

5.7MEDIUM

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
17 July 2026

What is CVE-2026-9602?

The Mattermost Desktop App has a vulnerability that affects versions up to and including 6.2. This flaw allows an attacker controlling a malicious server to send malformed payloads from the Mattermost Web App to the Desktop App. As a result, the Desktop App can be forced to crash, creating a denial of service condition. This vulnerability highlights the importance of payload validation in ensuring application security.

Affected Version(s)

Mattermost 0 <= 6.0.2

Mattermost 0 <= 5.6.13

Mattermost 6.3.0

References

https://mattermost.com/security-updates
vendor-advisory

CVSS V3.1

Score:
5.7
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

game0v3r
.