Description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the nnef-oam route group without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can hit the OAM route with no Authorization header at all and the handler returns 200 OK. The current OAM handler is a stub that returns null, but the structural defect is route-group-scoped: the entire OAM route group has no inbound auth middleware, so every future OAM operation added to this group inherits the missing auth boundary by default. This vulnerability is fixed in 4.2.2.
Affected products
free5gc: free5gc
References4
- github.com/free5gc/free5gc/security/advisories/GHSA-cmpj-2x3g-m… ExploitVendor Advisory
- github.com/free5gc/free5gc/security/advisories/GHSA-cmpj-2x3g-m… ExploitVendor Advisory
- github.com/free5gc/nef/pull/23 Issue TrackingPatch
- github.com/free5gc/free5gc/issues/861 ExploitIssue Tracking
Metrics
- CVSS 3.1
-
10.0
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H - EPSS — exploit probability
- 0% percentile: 24 · as of 14 November 2026
- CWE
- CWE-306CWE-862
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