Vulnerability · Published Aug 21, 2025 · Assigned by Mattermost
CVE-2025-49222Mattermost Shared Channel Upload Type Validation Bypass
Medium 6.8
In plain English
A medium-severity unrestricted file upload in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | 10.8.4 | GHSA-q453-638c-h4mr |
| Go | github.com/mattermost/mattermost-server | 10.5.9 | GHSA-q453-638c-h4mr |
| Go | github.com/mattermost/mattermost-server | 9.11.18 | GHSA-q453-638c-h4mr |
| Go | github.com/mattermost/mattermost-server | 10.9.3 | GHSA-q453-638c-h4mr |
| Go | github.com/mattermost/mattermost-server | 10.10.1 | GHSA-q453-638c-h4mr |
| Go | github.com/mattermost/mattermost-server | 10.10.1+incompatible, 10.5.9+incompatible, 10.8.4+incompatible, 10.9.3+incompatible, 9.11.18+incompatible | GO-2025-3904 |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GHSA-q453-638c-h4mr |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2025-3904 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2025-3904 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GHSA-q453-638c-h4mr |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20250708173752-d6b35c41f0ae5 | GHSA-q453-638c-h4mr |
| Go | github.com/mattermost/mattermost/server/v8 | no fix listed | GO-2025-3904 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 10.8.0 – through 10.8.310.5.0 – through 10.5.89.11.0 – through 9.11.1710.9.0 – through 10.9.210.10.0 – through 10.10.0 |
Weakness: CWE-434 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N