CVE-2026-44321: 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…

PriorityP342high7.5CVSS 3.1

AVNACLPRNUINSUCNINAH

EPSS

0.36%

28.3th percentile

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

2 ranges

Vendor	Product	Version range	Fixed in
free5gc	free5gc	< 4.2.2	4.2.2
github.com	free5gc_smf	0 – 1.4.3	—

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