CVE-2026-27643: free5GC has improper error handling in NEF with information exposure
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 NnefPfdManagement 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.
Affected Software
Remediation
Patch Available
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2026-27643?
CVE-2026-27643 is classified as a high-severity vulnerability due to improper error handling that leads to information exposure.
How do I fix CVE-2026-27643?
To fix CVE-2026-27643, you should update the free5GC UDR to version 1.4.2 or later, which addresses this error handling issue.
What types of information are exposed due to CVE-2026-27643?
CVE-2026-27643 leads to the exposure of internal parsing error details that could be leveraged by attackers.
Which versions of free5GC UDR are affected by CVE-2026-27643?
CVE-2026-27643 affects versions of free5GC UDR up to and including 1.4.1.
Can CVE-2026-27643 affect the security of a 5G network?
Yes, CVE-2026-27643 can compromise the security of a 5G network by leaking sensitive error information that may aid in further attacks.