CVE-2026-33065: free5GC UDM incorrectly returns 500 for empty supi path parameter in DELETE sdm-subscriptions request

Vulnerability summary

CVE-2026-33065 is a medium (CVSS 6.9) vulnerability in free5gc. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 37.4% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 20-03-2026
   PublishedVulnerability first disclosed.
2. 20-03-2026
   Last modifiedVulnerability information updated.

Description

Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. In versions prior to 1.4.2, the UDM incorrectly converts a downstream 400 Bad Request (from UDR) into a 500 Internal Server Error when handling DELETE requests with an empty supi path parameter. This leaks internal error handling behavior and makes it difficult for clients to distinguish between client-side errors and server-side failures. When a client sends a DELETE request with an empty supi (e.g., double slashes // in URL path), the UDM forwards the malformed request to UDR, which correctly returns 400. However, UDM propagates this as 500 SYSTEM_FAILURE instead of returning the appropriate 400 error to the client. This violates REST API best practices for DELETE operations. The issue has been patched in version 1.4.2.

• CWE-209Generation of Error Message Containing Sensitive InformationThe product generates an error message that includes sensitive information about its environment, users, or associated data.