GHSA-6rgm-gr97-x3j5 is a high-severity (CVSS 8.2) CWE-862 vulnerability in github.com/free5gc/pcf. A fix is available for github.com/free5gc/pcf — see the affected versions and patch details below.
Free5GC PCF: Missing authentication middleware in Npcf_SMPolicyControl allows access to SM policy handlers and disclosure of subscriber SUPI
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-6rgm-gr97-x3j5.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-6rgm-gr97-x3j5 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/free5gc/pcfReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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-policiesGET /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}POST /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/updatePOST /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
- Deploy free5GC with PCF reachable on the SBI network.
- Use the PoC against the PCF service without an
Authorizationheader: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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/free5gc/pcf | all versions | 1.4.3go get github.com/free5gc/pcf@v1.4.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/free5gc/pcf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/free5gc/pcf to 1.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6rgm-gr97-x3j5 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-6rgm-gr97-x3j5 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-6rgm-gr97-x3j5. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-6rgm-gr97-x3j5 in your dependencies?
O3 Security finds GHSA-6rgm-gr97-x3j5 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.