Vulnerability Advisory : Under certain configurations, file artifacts uploaded to the Dossier and Slides apps did not inherit security markings of their parent artifact. This lack of security markings could lead to unintended access to the uploaded files. with LOW Attack Complexity

### Details On October 1, 2025, Palantir discovered that images uploaded through the Dossier front-end app were not being marked correctly with the proper security levels. The regression was traced back to a change in May 2025, which was meant to allow file uploads to be shared among different artifacts (e.g. other dossiers and presentations). On deployments configured with CBAC, the front-end would present a security picker dialog to set the security level on the uploads, thereby mitigating the issue. On deployments without a CBAC configuration, no security picker dialog appears, leading to a security level of CUSTOM with no markings or datasets selected. The resulting markings and groups for the file uploads thus will be only those added by the “Default authorization rules” defined in the Auth Chooser configuration. On most environments, it is expected that the “Default authorization rules" only add the Everyone group.