CVE-2026-44321: high-severity vulnerability in free5gc
free5GC: SMF UPI POST /upi/v1/upNodesLinks exits the SMF process on overlapping UE pools (unauthenticated, reachable Fatalf)
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.4%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
free5gc · free5gcRelated CVEs — free5gc
In the same product, most dangerous first.
CVE-2026-53551MEDIUMfree5GC AUSF: null byte injection in supiOrSuci causes HTTP 500 internal service failureEPSS 0.7%CVE-2026-55068CRITICALfree5GC: NRF nnrf-nfm lacks NF Profile input validation — enables NF Registration Poisoning with arbitrary service endpointsEPSS 0.6%CVE-2026-47780MEDIUMfree5GC: UDR Improper ueId validation in free5GC EE subscription handlers allows arbitrary identifier persistenceEPSS 0.5%CVE-2026-40245HIGHFree5GC: UDR nudr-dr influenceData/subs-to-notify leaks SUPI in error response body without authenticationEPSS 0.5%CVE-2026-33064HIGHfree5GC UDM DataChangeNotification Procedure Panic Due to Nil Pointer DereferenceEPSS 0.5%CVE-2026-40247HIGHfree5gc UDR improper path validation allows unauthenticated access to Traffic Influence SubscriptionsEPSS 0.5%