CVE-2026-44321
free5GC's SMF UPI POST /upi/v1/upNodesLinks exits the SMF process on overlapping UE pools (unauthenticated, reachable Fatalf)
Impact
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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/free5gc/smf | <= 1.4.3 | none recorded |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Free5gc | Free5gc | before 4.2.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-44qj-cghf-9p97
- https://github.com/free5gc/free5gc/security/advisories/GHSA-44qj-cghf-9p97
- https://github.com/free5gc/free5gc/issues/906
- https://github.com/free5gc/smf/pull/203
- https://github.com/free5gc/smf/commit/e0974e07ddab44a67d36a563cca383b2449e33e5
- https://nvd.nist.gov/vuln/detail/CVE-2026-44321