CVE-2025-20621

Webapp crash via object that can't be cast to String in Attachment Field

CVSS 6.5 MEDIUMEPSS 0.4%CWE-1287

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.5EPSS 0.4%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

16 Jan 2025Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

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

Affected products

Mattermost · Mattermost

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References

https://mattermost.com/security-updates