CVE-2026-27642

MEDIUM EPSS 39.4%
Published Feb 24, 20264mo ago · Modified Jun 17, 20261w ago
6.6 CVSS 4.0
Medium
Find Similar
Published Feb 24, 2026 4mo ago
Last Modified Jun 17, 2026 1w ago

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 Details

Base Score
6.6
Exploitability
—
Impact
—
Vector string
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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
39.4% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-20 Improper Input Validation Validation

Affected Products 1

VendorProductVersionRange
free5gcudm* ≤1.4.1

References 4

  • github.com https://github.com/free5gc/free5gc/issues/749
    ExploitIssue TrackingVendor Advisory
  • github.com https://github.com/free5gc/free5gc/security/advisories/GHSA-h4wg-rp7m-8xx4
    Vendor Advisory
  • github.com https://github.com/free5gc/udm/commit/a7af2321ddea6368c43835f90f6d1b9d67dd2ea1
    Patch
  • github.com https://github.com/free5gc/udm/pull/75
    Issue TrackingPatch

Remediation

  • github.com https://github.com/free5gc/udm/commit/a7af2321ddea6368c43835f90f6d1b9d67dd2ea1
    Patch
  • github.com https://github.com/free5gc/udm/pull/75
    Issue TrackingPatch