CVE-2025-53709 is a medium-severity vulnerability affecting Palantir's secure-upload service (com.palantir.secupload:secure-upload), a data submission platform that validates single-use tokens for channel submissions. The vulnerability arises from improper or missing authorization checks when actors attempt to access resources or perform actions. Specifically, privileged users within one enrollment could exploit the service to select email templates not originally created for their enrollment, potentially leading to unauthorized data upload requests. Moreover, authenticated privileged users could abuse an endpoint to redirect existing submission channels to datasets under their control, effectively hijacking data flows. Additionally, an endpoint responsible for domain validation permitted unauthenticated users to enumerate existing enrollments, exposing sensitive metadata about the system's structure. Other endpoints allowed enumeration of resources by known resource IDs (RIDs) across enrollments, further increasing information disclosure risks. These issues collectively indicate a failure in enforcing strict access controls and authorization boundaries between enrollments and users. The vulnerability affects all versions of the secure-upload service prior to the patched release 0.815.0, which has been automatically deployed to all Apollo-managed Foundry instances. The CVSS 3.1 base score is 5.4, reflecting a medium severity level due to network exploitability, low attack complexity, required privileges, no user interaction, and limited confidentiality and integrity impacts without availability impact. No known exploits are currently reported in the wild. The vulnerability primarily compromises confidentiality and integrity by enabling unauthorized data access and manipulation through privilege abuse and information disclosure via enumeration endpoints.

For European organizations using Palantir Foundry with the secure-upload service, this vulnerability could lead to unauthorized access and manipulation of sensitive data submissions. Privileged users abusing the authorization flaws might redirect data channels to datasets they control, potentially causing data leakage or corruption. The ability for unauthenticated actors to enumerate enrollments and resource existence increases the risk of targeted attacks, reconnaissance, and subsequent exploitation. This could be particularly impactful for sectors handling sensitive or regulated data such as finance, healthcare, and government agencies within Europe. The exposure of enrollment metadata may also facilitate social engineering or insider threat activities. While the vulnerability does not directly cause denial of service, the integrity and confidentiality risks could undermine trust in data submission processes and compliance with data protection regulations like GDPR. Organizations relying on Apollo-managed Foundry instances benefit from automatic patch deployment, but those with self-managed or older versions remain at risk. Overall, the threat could disrupt secure data workflows and expose sensitive information, necessitating prompt remediation to maintain operational security and regulatory compliance.

European organizations should verify that their Palantir secure-upload service is updated to version 0.815.0 or later, ensuring the patch addressing CVE-2025-53709 is applied. For self-managed instances, immediate manual patching is critical. Organizations should audit privileged user roles and permissions within the secure-upload environment to enforce the principle of least privilege, limiting the ability to select email templates or redirect submission channels outside their enrollment scope. Implement monitoring and alerting on unusual activities such as channel redirections or access attempts to unauthorized templates. Restrict access to domain validation and resource enumeration endpoints by applying additional authentication or network-level controls (e.g., IP whitelisting, VPN access) to prevent unauthenticated enumeration. Conduct regular security assessments and penetration tests focused on authorization controls within the secure-upload service. Additionally, review and enhance logging to capture detailed access and modification events for forensic analysis. Finally, educate privileged users on secure usage policies to reduce insider risk and ensure compliance with data handling standards.