free5GC UDM Exposes Internal Details to Remote Attackers

Summary

Remote attackers can inject malicious characters into the free5GC UDM system, exposing internal error messages and potentially allowing them to identify the system's configuration. This affects all free5GC deployments using the UDM Nudm_UEAU service. To fix this issue, update to the latest version of free5GC UDM (version 1.4.2 or later) by applying the official patch.

What to do

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

Affected software

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

Original title

free5gc UDM provides Unified Data Management (UDM) for free5GC, an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.1, remote attackers can inje...

Original description

free5gc UDM provides Unified Data Management (UDM) for free5GC, an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.1, remote attackers can inject control characters (e.g., %00) into the supi parameter, triggering internal URL parsing errors (net/url: invalid control character). This exposes system-level error details and can be used for service fingerprinting. All deployments of free5GC using the UDM Nudm_UEAU service may be affected. free5gc/udm pull request 75 contains a fix for the issue. No direct workaround is available at the application level. Applying the official patch is recommended.

nvd CVSS3.1 7.5

nvd CVSS4.0 6.6

Vulnerability type

CWE-20 Improper Input Validation

https://github.com/free5gc/free5gc/issues/749 Exploit Issue Tracking Vendor Advisory
https://github.com/free5gc/free5gc/security/advisories/GHSA-h4wg-rp7m-8xx4 Vendor Advisory
https://github.com/free5gc/udm/commit/a7af2321ddea6368c43835f90f6d1b9d67dd2ea1 Patch
https://github.com/free5gc/udm/pull/75 Issue Tracking Patch