vulnerability / NVI-00018289 / Revision 1
free5GC's PCF npcf-smpolicycontrol POST /sm-policies panics on downstream UDR/OpenAPI 404 via nil pointer dereference
GitHub lists this reviewed advisory for github.com/free5gc/pcf. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
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7.5 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/free5gc/pcf
source listed< 1.4.2
### Summary 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 v4.2.1 this endpoint is also reachable WITHOUT an `Authorization` header because the PCF `Npcf_SMPolicyControl` route group is mounted without inbound auth middleware (see free5gc/free5gc#844). So in the validation lab the trigger is fully unauthenticated. ### Details Validated against the PCF container in the official Docker compose lab. - free5GC version: `v4.1.0` (originally reported on v4.1.0; same defect present in v4.2.1
03 / Response
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- investigate
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-wr8j-6chw-gm6p ↗
GitHub Advisory Database · vendor advisory
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- Revision 1 ·
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