Ghostwire

CVE-2026-18560: Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to validate user’s...

MEDIUM CVSS 4.3

Published: October 16, 2026 | Last Modified: October 16, 2026

Description

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to validate user’s permissions before other validations which allows non-content reviewers to infer a post’s flagged status via direct API call.. Mattermost Advisory ID: MMSA-2026-00754

Ghostwire Analysis — What This Means Practically

Medium CVSS score indicates moderate risk — exploitation requires specific conditions or results in limited impact.

This analysis is generated by Ghostwire from NVD, CISA KEV, EPSS, and open-source intelligence data. Verify findings through primary sources before acting.

Security Coverage (1 articles)

References

mattermost.com/security-updates