CVE-2026-6345

Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614

CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0004

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-522 CWE-522

Affected Products

Vendor	Product	Versions
mattermost	mattermost_server	10.11.0 — 10.11.14
mattermost	mattermost_server	11.4.0 — 11.4.4
mattermost	mattermost_server	11.5.0 — 11.5.2

References

Advisories & Patches

https://mattermost.com/security-updates

Frequently Asked Questions

What is CVE-2026-6345? +

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614 It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-6345? +

CVE-2026-6345 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0004, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-6345? +

CVE-2026-6345 affects products from mattermost, specifically: mattermost_server. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-6345? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-15621

Insufficiently Protected Credentials in Sparx Systems Pty Ltd. Sparx Enterprise Architect. Client does not verify the receiver of OAuth2 credentials …

CVE-2025-15622

Insufficiently Protected Credentials vulnerability in Sparx Systems Pty Ltd. Sparx Enterprise Architect. Client reveals plaintext OAuth2 client secretDesktop client decodes …

CVE-2024-12799

Insufficiently Protected Credentials vulnerability in OpenText Identity Manager Advanced Edition on Windows, Linux, 64 bit allows Privilege Abuse. This vulnerability …

CVE-2025-1886

Pass-Back vulnerability in versions prior to 2025.35.000 of Sage 200 Spain. This vulnerability allows an authenticated attacker with administrator privileges …

CVE-2025-2908

The exposure of credentials in the call forwarding configuration module in MeetMe products in versions prior to 2024-09 allows an …

CVE-2025-22372

Insufficiently Protected Credentials vulnerability in SicommNet BASEC on SaaS allows Password Recovery. Passwords are either stored in plain text using …