CVE-2026-44321 — free5GC: SMF UPI POST /upi/v1/upNodesLinks exits the SMF process on overlapping UE pools (unauthenticated, reachable Fatalf)
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 …
Published: 2026-05-27 · CVSS: 7.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7