Free5GC PCF: Missing authentication middleware in Npcf_SMPolicyControl allows access to SM policy handlers and disclosure of subscriber SUPI

### Summary PCF Npcf_SMPolicyControl missing authentication middleware allows unauthenticated access to SM policy handlers and disclosure of subscriber SUPI ### Details In `NewServer()`, the `smPolicyGroup` route group is created and routes are applied without attaching the router authorization middleware. In contrast, other PCF service groups such as `Npcf_PolicyAuthorization` do attach `RouterAuthorizationCheck` before route registration. Because the middleware is missing, requests to the following endpoints can reach business logic even when no valid OAuth token is provided: - `POST /npcf-smpolicycontrol/v1/sm-policies` - `GET /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}` - `POST /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/update` - `POST /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/delete` This is visible at runtime because unauthenticated requests return business-level responses such as `400` or `404` instead of being rejected with `401` before handler execution. Under valid lab preconditions (existing UE/session context and related policy data), unauthenticated `POST /sm-policies` can succeed with `201`, and unauthenticated `GET /sm-policies/{id}` can succeed with `200` and return policy context containing subscriber identifiers including `supi`. The root cause is missing router auth enforcement for `Npcf_SMPolicyControl`. Upstream also fixed this by adding `RouterAuthorizationCheck` to `smPolicyGroup` (and `uePolicyGroup`) in free5gc/pcf PR #63. ### PoC 1. Deploy free5GC with PCF reachable on the SBI network. 2. Use the PoC against the PCF service **without** an `Authorization` header: ```bash go run /home/ubuntu/free5gc/tools/npcf-smpolicy-noauth-poc/main.go \ --pcf-root /home/ubuntu/free5gc/NFs/pcf \ --pcf-url http://10.100.200.9:8000 \ --timeout 4s Observe that unauthenticated requests to Npcf_SMPolicyControl return business responses instead of 401. ### Impact This is an authentication/authorization bypass on a network-accessible SBI service. Any unauthenticated actor able to reach the PCF SBI interface can invoke Npcf_SMPolicyControl handlers directly.

Source published

7 May 2026 01:58:42 UTC

Source modified

25 Jun 2026 19:56:20 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Publisher rating · HIGH