CVE-2025-69251 free5GC has Improper Input Validation in UDM, Leading to Information Exposure

Medium 6.6 Published 23 Feb 2026 Updated 25 Feb 2026

Remote attackers can inject control characters into the UDM service to expose system details and aid in service fingerprinting.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2025-69251?

CVE-2025-69251 is a medium-severity vulnerability in free5gc udm, published on 23 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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 ueId parameter, triggering internal URL parsing errors (net/url: invalid control character). This exposes system implementation details and can aid in service fingerprinting. All deployments of free5GC using the UDM Nudm_UECM service may be affected. free5gc/udm pull request 76 contains a fix for the issue. No direct workaround is available at the application level. Applying the official patch is recommended.

Weakness: CWE-20

Which versions are affected by CVE-2025-69251?

It affects 1 product.

Products include Free5gc Udm.

How do I fix CVE-2025-69251?

No fix has been published for CVE-2025-69251 yet. Limit exposure of the affected software until one is available.

Is CVE-2025-69251 being exploited?

There is no known exploitation of CVE-2025-69251 in the wild and no public exploit code.

Sources

Also known as GHSA-pwxh-4qh4-hgpq.