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.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/free5gc/free5gc/security/advisories/GHSA-cmpj-2x3g-m7g3 Exploit, Vendor Advisory
- https://github.com/free5gc/nef/pull/23 Issue Tracking, Patch
- https://github.com/free5gc/free5gc/security/advisories/GHSA-cmpj-2x3g-m7g3 Exploit, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 10.0 · free5gcNVD modified 2026-10-14 20:10
Affected (CPE criteria) 1
cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*
References 4
- https://github.com/free5gc/free5gc/issues/861 Exploit, Issue Tracking
- https://github.com/free5gc/free5gc/security/advisories/GHSA-cmpj-2x3g-m7g3 Exploit, Vendor Advisory
- https://github.com/free5gc/nef/pull/23 Issue Tracking, Patch
- https://github.com/free5gc/free5gc/security/advisories/GHSA-cmpj-2x3g-m7g3 Exploit, Vendor Advisory