CVE-2026-44316 affects free5GC, an open-source 5G core network implementation. Prior to version 4.2.2, the PCF POST handler for sm-policies panics with a nil-pointer dereference when downstream UDR lookups return 404 errors. The vulnerability allows attackers to cause HTTP 500 responses instead of proper 4xx codes through crafted POST requests. In version 4.2.1, the endpoint is also accessible without authorization headers due to missing authentication middleware. The issue is triggered by POST requests with input causing UDR lookup failures, such as unknown DNN values. The vulnerability has been fixed in version 4.2.2.