Mattermost doesn't prevent disclosure of created user password

CVE-2026-6345 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
—
Source code
Browse source ↗
Published (advisory)
2026-05-18 09:31:48 UTC
Updated
2026-06-01 15:34:43 UTC
GitHub reviewed
2026-06-01 15:34:40 UTC
NVD published
2026-05-18 09:16:23 UTC

EPSS Score

Score Percentile
0.04% 10.93%

CVSS Scores

Base score Version Severity Vector
6.5 3.1 —
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

Type Value
GHSA GHSA-wvgv-4fc3-2rcp ↗
CVE CVE-2026-6345 ↗

CWEs

CWE id Name
CWE-522 Insufficiently Protected Credentials

Affected packages (5)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
go github.com/mattermost/mattermost/server/v8 >= 11.5.0, < 11.5.2 11.5.2 —
go github.com/mattermost/mattermost/server/v8 >= 10.11.0, < 10.11.14 10.11.14 —
go github.com/mattermost/mattermost/server/v8 >= 11.4.0, < 11.4.4 11.4.4 —
go github.com/mattermost/mattermost/server/v8 < 8.0.0-20260311102650-3057ae7e83e9 8.0.0-20260311102650-3057ae7e83e9 —
go github.com/mattermost/mattermost-server < 5.3.2-0.20260311102650-3057ae7e83e9 5.3.2-0.20260311102650-3057ae7e83e9 —

References

cvelogic Threat Intelligence