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Mattermost doesn't prevent disclosure of created user password

Moderate severity GitHub Reviewed Published May 18, 2026 to the GitHub Advisory Database • Updated Jun 1, 2026

Package

gomod github.com/mattermost/mattermost-server (Go)

Affected versions

< 5.3.2-0.20260311102650-3057ae7e83e9

Patched versions

5.3.2-0.20260311102650-3057ae7e83e9
gomod github.com/mattermost/mattermost/server/v8 (Go)
>= 11.5.0, < 11.5.2
>= 10.11.0, < 10.11.14
>= 11.4.0, < 11.4.4
< 8.0.0-20260311102650-3057ae7e83e9
11.5.2
10.11.14
11.4.4
8.0.0-20260311102650-3057ae7e83e9

Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 doesn't 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

References

Published by the National Vulnerability Database May 18, 2026
Published to the GitHub Advisory Database May 18, 2026
Reviewed Jun 1, 2026
Last updated Jun 1, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(11th percentile)

Weaknesses

Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval. Learn more on MITRE.

CVE ID

CVE-2026-6345

GHSA ID

GHSA-wvgv-4fc3-2rcp

Source code

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