CVE-2026-27642
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).
Does this matter?
Lower severity and a low EPSS score (0.51%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 6.6 MEDIUMCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.51% probability · 42th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Affected
- free5gc/udm
- Source
- security-advisories@github.com
References
- https://github.com/free5gc/free5gc/issues/749Exploit, Issue Tracking, Vendor Advisory
- https://github.com/free5gc/free5gc/security/advisories/GHSA-h4wg-rp7m-8xx4Vendor Advisory
- https://github.com/free5gc/udm/commit/a7af2321ddea6368c43835f90f6d1b9d67dd2ea1Patch
- https://github.com/free5gc/udm/pull/75Issue Tracking, Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.