CVE-2025-20621
MEDIUMCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
3Description
Mattermost versions 10.2.x <= 10.2.0, 9.11.x <= 9.11.5, 10.0.x <= 10.0.3, 10.1.x <= 10.1.3 fail to properly handle posts with attachments containing fields that cannot be cast to a String, which allows an attacker to cause the webapp to crash via creating and sending such a post to a channel.
Analysis
Mattermost versions 10.2.x <= 10.2.0, 9.11.x <= 9.11.5, 10.0.x <= 10.0.3, 10.1.x <= 10.1.3 fail to properly handle posts with attachments containing fields that cannot be cast to a String, which. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Technical Context
This vulnerability is classified under CWE-1287. Mattermost versions 10.2.x <= 10.2.0, 9.11.x <= 9.11.5, 10.0.x <= 10.0.3, 10.1.x <= 10.1.3 fail to properly handle posts with attachments containing fields that cannot be cast to a String, which allows an attacker to cause the webapp to crash via creating and sending such a post to a channel. Affected products include: Mattermost Mattermost Server.
Affected Products
Mattermost Mattermost Server.
Remediation
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
Priority Score
Vendor Status
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External POC / Exploit Code
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