Improper input validation in Free5gc Udm
CVE-2025-69251
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 ueId parameter, triggering internal URL parsing errors (net/url: invalid control character). This exposes system implementation details and can aid in service fingerprinting. All deployments of free5GC using the UDM Nudm_UECM service may be affected. free5gc/udm pull request 76 contains a fix for the issue. No direct workaround is available at the application level. Applying the official patch is recommended.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.005 (39.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000
Affected products
- Free5gc Udm — versions <= 1.4.1
Weakness classification (CWE)
References
- github.com/free5gc/free5gc/security/advisories/GHSA-pwxh-4qh4-hgpq (Vendor Advisory)
- github.com/free5gc/free5gc/issues/751 (Exploit, Issue Tracking, Vendor Advisory)
- github.com/free5gc/free5gc/issues/76 (Exploit, Issue Tracking, Vendor Advisory)
- github.com/free5gc/udm/commit/504b14458d156558b3c0ade7107b86b3d5e72998 (Patch)
Frequently asked questions
- What is CVE-2025-69251?
- CVE-2025-69251 is a medium-severity vulnerability in Free5gc Udm, classified under Improper Input Validation. CVSS score: 5.3/10. Published 2026-02-24.
- How severe is CVE-2025-69251?
- Medium severity. CVSS v3 base score is 5.3 out of 10.