CVE-2025-49222

Mattermost Shared Channel Upload Type Validation Bypass

State: Published
Severity: 6.8 Medium
Published: Aug 21, 2025
Updated: Aug 21, 2025
Reserved: Jul 22, 2025

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.

Scores

CVSS	Score	Vector	Source
3.1	6.8 Medium	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N	Mattermost

Weaknesses

CWE-434 Unrestricted Upload of File with Dangerous Type

Affected Products

Product	Versions
MattermostMattermost	10.8.0 through 10.8.3Affected 10.5.0 through 10.5.8Affected 9.11.0 through 9.11.17Affected 10.9.0 through 10.9.2Affected 10.10.0 through 10.10.0Affected 10.11.0Not affected 10.8.4Not affected 10.5.9Not affected 9.11.18Not affected 10.9.3Not affected 10.10.1Not affected

References

https://mattermost.com/security-updates

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