CVE-2026-27642

free5GC has Improper Input Validation in UDM UEAU Service

HIGH
7.5
CVSS Score
Published: February 24, 2026 at 12:18 AM UTC
Updated: June 17, 2026 at 10:27 AM UTC
1 product affected across 1 vendorUdm

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 1.4.1<= 1.4.1

References (4)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/free5gc/free5gc/security/advisories/GHSA-h4wg-rp7m-8xx4
x_refsource_MISCExploitIssue TrackingVendor Advisory
Source: cverecord
https://github.com/free5gc/free5gc/issues/749
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/free5gc/udm/pull/75

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-20

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