Information disclosure in Mattermost
CVE-2026-75587
Mattermost Desktop App versions <=6.2 6.2.2.0 fail to redact the pre-auth secret when generating a diagnostics report, which allows a local attacker with access to a user's diagnostics report or log files to obtain the plaintext pre-auth secret configured for a connected server via inspecting the Server Connectivity (Step-3) diagnostics output. Mattermost Advisory ID: MMSA-2026-00716
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.6 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.001 (2.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 2.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000
Affected products
- Mattermost — versions 0, 6.3.0, 6.2.3.0
- Mattermost Desktop
Weakness classification (CWE)
References
- mattermost.com/security-updates (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-75587?
- CVE-2026-75587 is a low-severity vulnerability in Mattermost, classified under Information Disclosure. CVSS score: 3.6/10. Published 2026-08-17.
- How severe is CVE-2026-75587?
- Low severity. CVSS v3 base score is 3.6 out of 10.