What’s Vulnerable › Vulnerabilities
CVE-2026-19600: Mattermost logs plaintext authentication tokens in debug-level server logs on failed auth attempts
- Severity: medium (CVSS 4.9 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-10-16 · updated 2026-10-27
- Weakness: CWE-532
Description
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize authentication tokens before writing them to server log entries, which allows an attacker with access to server logs to obtain valid session tokens or OAuth access tokens and impersonate authenticated users via the debug-level Mattermost server log.. Mattermost Advisory ID: MMSA-2026-00763
Affected products
- Mattermost: from 11.7.0 before 11.7.10; from 11.8.0 before 11.8.6; from 11.9.0 before 11.9.2; from 11.10.0 before 11.10.2 — fixed in 11.7.10, 11.8.6, 11.9.2, 11.10.2
- Mattermost: from 11.9.0 through 11.9.1; from 11.8.0 through 11.8.5; from 11.7.0 through 11.7.10; from 11.10.0 through 11.10.1
How to fix
Upgrade to a fixed version: Mattermost 11.7.10, 11.8.6, 11.9.2, 11.10.2. Check the vendor advisory for mitigations.
References
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