Description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's SMF mounts the UPI management route group without inbound OAuth2 middleware. The POST /upi/v1/upNodesLinks create-or-update handler accepts attacker-controlled JSON and passes it directly into UpNodesFromConfiguration(), which calls logger.InitLog.Fatalf(...) on several validation failures. One confirmed path is the UE-IP-pool overlap check: a single unauthenticated POST that adds a new UPF whose pool overlaps an existing UPF terminates the entire SMF process (docker ps shows Exited (1)), not just the goroutine. This vulnerability is fixed in 4.2.2.
Affected products
free5gc: free5gc
References5
- github.com/free5gc/free5gc/security/advisories/GHSA-44qj-cghf-9… ExploitVendor Advisory
- github.com/free5gc/free5gc/security/advisories/GHSA-44qj-cghf-9… ExploitVendor Advisory
- github.com/free5gc/smf/commit/e0974e07ddab44a67d36a563cca383b24… Patch
- github.com/free5gc/smf/pull/203 Issue TrackingPatch
- github.com/free5gc/free5gc/issues/906 ExploitIssue Tracking
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 31 · as of 14 November 2026
- CWE
- CWE-306CWE-617CWE-862
Could this be exploited in your environment?
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