Vulnerability in Mattermost Allows Authenticated Users to Publish Unvalidated System Posts
CVE-2026-93847

3.5LOW

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
26 October 2026

What is CVE-2026-93847?

Mattermost versions 11.7.x up to and including 11.7.10 have a vulnerability that fails to correctly validate reserved system post types during the scheduled post creation and publication processes. This flaw permits an authenticated channel member to publish messages that appear as trusted system events through the scheduled post endpoint, potentially undermining the trustworthiness of the messaging system. For further details, refer to the official advisory.

Affected Version(s)

Mattermost 11.7.0 <= 11.7.10

Mattermost 11.11.0

Mattermost 11.7.11

References

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

CVSS V3.1

Score:
3.5
Severity:
LOW
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

arang
.