Description
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.
Affected products
free5gc: free5gc
References6
- github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-2… ExploitVendor Advisory
- github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-2… ExploitVendor Advisory
- github.com/free5gc/nef/commit/f110517b1189801950b50668a59339868… Patch
- github.com/free5gc/nef/pull/25 Issue TrackingPatch
- github.com/free5gc/free5gc/issues/924 ExploitIssue Tracking
- github.com/free5gc/free5gc/issues/924 ExploitIssue Tracking
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 35 · as of 14 November 2026
- CWE
- CWE-20CWE-617CWE-755
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