CVE-2025-49222 - CVE House
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Status published Medium CVE-2025-49222

Mattermost Shared Channel Upload Type Validation Bypass

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • daw10

References

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Affected Vendor

Affected Software

Mattermost
Vulnerable Versions:
10.8.0, 10.5.0, 9.11.0, 10.9.0, 10.10.0, 10.11.0, 10.8.4, 10.5.9, 9.11.18, 10.9.3, 10.10.1

Timeline

Official Publish: August 21st, 2025
Last Modified: August 21st, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

Weaknesses (CWE)

CWE-434

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application
Initial Access
T1505.003 Web Shell
Persistence
T1105 Ingress Tool Transfer
Command and Control
T1059 Command and Scripting Interpreter
Execution
T1565.002 Stored Data Manipulation
Impact