free5GC SMF Crashes When Processing Bad Network Messages

Summary

A flaw in free5GC's Session Management Function (SMF) causes it to crash when receiving a corrupted message. This can allow attackers to disrupt the network. To protect yourself, consider blocking the PFCP interface to only allow trusted IP addresses and possibly filtering out bad messages at the network edge or implementing a workaround to prevent the SMF from crashing.

What to do

No fix is available yet. Check with your software vendor for updates.

Affected software

Vendor	Product	Affected versions	Fix available
free5gc	smf	<= 1.4.1	–

Original title

free5GC SMF provides Session Management Function for free5GC, an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.1, SMF panics and terminates w...

Original description

free5GC SMF provides Session Management Function for free5GC, an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.1, SMF panics and terminates when processing a malformed PFCP SessionReportRequest on the PFCP (UDP/8805) interface. No known upstream fix is available, but some workarounds are available. ACL/firewall the PFCP interface so only trusted UPF IPs can reach SMF (reduce spoofing/abuse surface); drop/inspect malformed PFCP SessionReportRequest messages at the network edge where feasible, and/or add recover() around PFCP handler dispatch to avoid whole-process termination (mitigation only).

nvd CVSS3.1 7.5

nvd CVSS4.0 6.6

Vulnerability type

CWE-476 NULL Pointer Dereference

https://github.com/free5gc/free5gc/issues/807 Exploit Issue Tracking
https://github.com/free5gc/free5gc/security/advisories/GHSA-vw8r-p7h3-g3xh Vendor Advisory