CVE-2025-49222CWE-434

Mattermost Shared Channel Upload Type Validation Bypass

Medium · published August 21, 2025

CVSS v3.1
6.8
EPSS
0%
Percentile
21.7
In the wild
Unconfirmed
What it is

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.

The record
Technical detail
CVSS v3.1
6.8 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00301 · 21.7th percentile
Weakness
CWE-434 · Unrestricted Upload of File with Dangerous Type
Published
2025-08-21T07:59Z
EPSS history
Timeline
  • 21 AUG 07:59Z
    Mattermost Shared Channel Upload Type Validation Bypass
    cvelistv5