free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF terminates the entire process when a stored PFD-subscription notifyUri cannot be reached. In PfdChangeNotifier.FlushNotifications(), the notifier calls NnefPFDmanagementNotify(...) and on any delivery error invokes logger.PFDManageLog.Fatal(err), which is os.Exit(1)-equivalent in Go. An attacker who can create a PFD subscription with an attacker-chosen notifyUri and then trigger a PFD change can deterministically kill NEF on the asynchronous delivery attempt -- the process exits with status 1, dropping NEF's entire SBI surface until restart. This vulnerability is fixed in 4.2.2.
Fix
Patch, vendor advisory and mitigation references on NVD 4
- https://github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-26pr Exploit, Vendor Advisory
- https://github.com/free5gc/nef/commit/f110517b1189801950b50668a593398687049074 Patch
- https://github.com/free5gc/nef/pull/25 Issue Tracking, Patch
- https://github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-26pr Exploit, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.5 · free5gcNVD modified 2026-10-14 20:10
Affected (CPE criteria) 1
cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*
References 6
- https://github.com/free5gc/free5gc/issues/924 Exploit, Issue Tracking
- https://github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-26pr Exploit, Vendor Advisory
- https://github.com/free5gc/nef/commit/f110517b1189801950b50668a593398687049074 Patch
- https://github.com/free5gc/nef/pull/25 Issue Tracking, Patch
- https://github.com/free5gc/free5gc/issues/924 Exploit, Issue Tracking
- https://github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-26pr Exploit, Vendor Advisory