CVE-2026-27642: free5GC has Improper Input Validation in UDM UEAU Service
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 NudmUEAU 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.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2026-27642?
CVE-2026-27642 is considered a high-severity vulnerability due to improper input validation allowing remote code injection.
How do I fix CVE-2026-27642?
To fix CVE-2026-27642, upgrade free5GC UDM to version 1.4.2 or later.
What impact does CVE-2026-27642 have on free5GC?
CVE-2026-27642 allows attackers to inject control characters, potentially leading to unauthorized access or exploitation.
Which versions of free5GC are affected by CVE-2026-27642?
CVE-2026-27642 affects free5GC UDM versions up to and including 1.4.1.
What components of free5GC does CVE-2026-27642 target?
CVE-2026-27642 specifically targets the Unified Data Management (UDM) component of free5GC.