CVE-2026-4858 PUBLISHED

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

Assigner: Mattermost
Reserved: 25.03.2026 Published: 21.05.2026 Updated: 21.05.2026

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

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
CVSS Score: 8

Attack Vector	Network	Scope	Changed
Attack Complexity	High	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	Required	Availability Impact	High

CVSS 3.1

Product Status

Vendor	Mattermost
Product	Mattermost
Versions	Default: unaffected affected from 11.6.0 to 11.6.0 (incl.) affected from 11.5.0 to 11.5.3 (incl.) affected from 11.4.0 to 11.4.4 (incl.) affected from 10.11.0 to 10.11.14 (incl.) Version 11.7.0 is unaffected Version 11.6.1 is unaffected Version 11.5.4 is unaffected Version 11.4.5 is unaffected Version 10.11.15 is unaffected

Solutions

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

Credits

daw10 finder

References

MMSA-2026-00640

Problem Types

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') CWE