CVE-2026-33065

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.

Weakness classification

• security-advisories@github.com: CWE-209

Primary references

• security-advisories@github.com — Exploit, Issue Tracking, Patch, Vendor Advisory
• security-advisories@github.com — Patch, Vendor Advisory
• security-advisories@github.com — Patch
• security-advisories@github.com — Issue Tracking, Patch