Vulnerability Details 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 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 16.6%
CVSS Severity
CVSS v3 Score 7.5
References
- https://github.com/free5gc/free5gc/issues/906
- https://github.com/free5gc/free5gc/security/advisories/GHSA-44qj-cghf-9p97
- https://github.com/free5gc/smf/commit/e0974e07ddab44a67d36a563cca383b2449e33e5
- https://github.com/free5gc/smf/pull/203
- https://github.com/free5gc/free5gc/security/advisories/GHSA-44qj-cghf-9p97
Products affected by CVE-2026-44321
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cpe:2.3:a:free5gc:free5gc:1.1.1
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cpe:2.3:a:free5gc:free5gc:3.0.1
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cpe:2.3:a:free5gc:free5gc:3.0.2
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cpe:2.3:a:free5gc:free5gc:3.0.3
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cpe:2.3:a:free5gc:free5gc:3.0.4
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cpe:2.3:a:free5gc:free5gc:3.0.5
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cpe:2.3:a:free5gc:free5gc:3.0.6
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cpe:2.3:a:free5gc:free5gc:3.0.7
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cpe:2.3:a:free5gc:free5gc:3.1.0
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cpe:2.3:a:free5gc:free5gc:3.1.1
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cpe:2.3:a:free5gc:free5gc:3.2.0
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cpe:2.3:a:free5gc:free5gc:3.2.1
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cpe:2.3:a:free5gc:free5gc:3.3.0
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cpe:2.3:a:free5gc:free5gc:3.4.0
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cpe:2.3:a:free5gc:free5gc:3.4.1
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cpe:2.3:a:free5gc:free5gc:3.4.2
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cpe:2.3:a:free5gc:free5gc:3.4.3
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cpe:2.3:a:free5gc:free5gc:3.4.4
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cpe:2.3:a:free5gc:free5gc:3.4.5
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cpe:2.3:a:free5gc:free5gc:4.0.0
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cpe:2.3:a:free5gc:free5gc:4.0.1
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cpe:2.3:a:free5gc:free5gc:4.1.0