CVE-2026-27642 MEDIUM

CVE-2026-27642: free5GC has Improper Input Validation in UDM UEAU Service

Vendor Free5Gc
Product udm
Weakness CWE-20 · Input validation
Published February 24, 2026
Last update February 26, 2026

CVSS base score

6.6/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

February 24, 2026 CVE published
February 26, 2026 Record updated