CVE-2026-4858

Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.

Published May 21, 2026 CVSS 3.1 · 8 High EPSS < 1% KEV · Not listed
Description
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to check integration URL for path traversal which allows an malicious authenticated user to call an arbitrary API via system admin Mattermost auth token using via path traversal in integration action URL.. Mattermost Advisory ID: MMSA-2026-00640

Remediation

Vendor Solution

Update Mattermost to versions 11.7.0, 11.6.1, 11.5.4, 11.4.5, 10.11.15 or higher.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-c4r7-j7pp-r8mp Mattermost has a Path Traversal issue
References
History
Type Values Removed Values Added
First Time appeared Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_server:11.6.0:*:*:*:*:*:*:*
Vendors & Products Mattermost mattermost Server
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Description Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to check integration URL for path traversal which allows an malicious authenticated user to call an arbitrary API via system admin Mattermost auth token using via path traversal in integration action URL.. Mattermost Advisory ID: MMSA-2026-00640
Title Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
Weaknesses CWE-22
References
Metrics cvssV3_1

{'score': 8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
May 22, 2026, 3:55 AM
Reserved
Mar 25, 2026, 3:58 PM
Status
Analyzed
Published
May 21, 2026, 9:16 AM
Modified
Jul 23, 2026, 4:10 PM