When adding attachments to ticket comments, another user can add attachments as well impersonating the orginal user. The attack requires a logged-in other user to know the UUID. While the legitimate user completes the comment, the malicious user can add more files to the comment. This issue affects OTRS: from 7.0.X through 7.0.48, from 8.0.X through 8.0.37, from 2023.X through 2023.1.1.
https://otrs.com/release-notes/otrs-security-advisory-2024-03/