CVE-2025-21088

Summary

CVE-2025-21088 is a vulnerability affecting Mattermost versions 10.2.x up to 10.2.0, 9.11.x up to 9.11.5, 10.0.x up to 10.0.3, and 10.1.x up to 10.1.3. This issue arises from the software's failure to adequately validate the style of proto supplied to an action's style in post.props.attachments. An attacker can exploit this vulnerability by providing maliciously crafted input, leading to a frontend crash. The consequence of this vulnerability is a potential denial-of-service (DoS) attack. Users of these Mattermost versions are advised to upgrade to the latest, secure versions as soon as possible to mitigate this risk.

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