CVE-2026-44316free5GC: PCF npcf-smpolicycontrol POST /sm-policies panics on downstream UDR/OpenAPI 404 via nil pointer dereference

Official description

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's PCF POST /npcf-smpolicycontrol/v1/sm-policies handler (HandleCreateSmPolicyRequest) panics with a nil-pointer dereference when a downstream OpenAPI consumer call (UDR lookup) returns 404 Not Found and the consumer wrapper returns err != nil together with a nil response struct. The handler logs the OpenAPI error and continues executing instead of returning, then dereferences the nil response struct on a subsequent line and panics. Gin recovery converts the panic into HTTP 500, so a single attacker-shaped POST returns 500 instead of a clean 4xx whenever the downstream lookup fails. The PCF process keeps running. The trigger is a single POST containing input that causes the downstream UDR lookup to fail (e.g. an unknown DNN). In 4.2.1 this endpoint is also reachable WITHOUT an Authorization header because the PCF Npcf_SMPolicyControl route group is mounted without inbound auth middleware. This vulnerability is fixed in 4.2.2.

Affected packages & fixed versions

Affected products (as reported)

References

• https://github.com/free5gc/free5gc/security/advisories/GHSA-wr8j-6chw-gm6p x_refsource_CONFIRM
• https://github.com/free5gc/free5gc/issues/803 x_refsource_MISC
• https://github.com/free5gc/pcf/pull/62 x_refsource_MISC
• https://github.com/free5gc/pcf/commit/df535f5524314620715e842baf9723efbeb481a7 x_refsource_MISC