CVE-2026-27643 free5GC has improper error handling in NEF with information exposure

Medium 6.6 Published 24 Feb 2026 Updated 26 Feb 2026

Attackers can obtain internal error details from the NEF component, aiding service fingerprinting in free5GC deployments.

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-2026-27643?

CVE-2026-27643 is a medium-severity vulnerability in free5gc udr, published on 24 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.1, the NEF component reliably leaks internal parsing error details (e.g., invalid character 'n' after top-level value) to remote clients, which can aid attackers in service fingerprinting. All deployments of free5GC using the Nnef_PfdManagement service may be affected. free5gc/udr pull request 56 contains a patch for the issue. There is no direct workaround at the application level. The recommendation is to apply the provided patch.

Weakness: CWE-209

Which versions are affected by CVE-2026-27643?

It affects 1 product.

Products include Free5gc Udr.

How do I fix CVE-2026-27643?

No fix has been published for CVE-2026-27643 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-27643 being exploited?

There is no known exploitation of CVE-2026-27643 in the wild and no public exploit code.

Sources

Also known as GHSA-6468-f87j-6g82.