CVE-2026-27642
free5GC has Improper Input Validation in UDM UEAU Service
- State
- Published
- Severity
- 6.6 Medium
- Published
- Feb 24, 2026
- Updated
- Feb 26, 2026
- Reserved
- Feb 20, 2026
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 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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.6 Medium | 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 | GitHub_M |
Weaknesses
- CWE-20 Improper Input Validation
Affected Products
| Product | Versions |
|---|---|
udmfree5gc |
|
References
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