What is CVE-2026-19601?

CVE-2026-19601 is a medium-severity vulnerability in Mattermost, classified under Insertion of Sensitive Information into Sent Data. CVSS score: 4.9/10. Published 2026-10-16.

How severe is CVE-2026-19601?

Medium severity. CVSS v3 base score is 4.9 out of 10.

Vulnerability in Mattermost

CVE-2026-19601

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 invalidate the stored AD/LDAP bind password when other connection settings (such as the server address) are changed, which allows a System Console administrator to disclose the plaintext bind password to an attacker-controlled server via the Test Connection / diagnostics feature. Mattermost Advisory ID: MMSA-2026-00764

Published 2026-10-16 · last modified 2026-10-16.

CVSS v3 metric

CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Mattermost

Weakness classification (CWE)

CWE-201 — Insertion of Sensitive Information into Sent Data

References

mattermost.com/security-updates (vendor-advisory)

Frequently asked questions

What is CVE-2026-19601?: CVE-2026-19601 is a medium-severity vulnerability in Mattermost, classified under Insertion of Sensitive Information into Sent Data. CVSS score: 4.9/10. Published 2026-10-16.
How severe is CVE-2026-19601?: Medium severity. CVSS v3 base score is 4.9 out of 10.