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CVE-2026-27642

free5GC has Improper Input Validation in UDM UEAU Service

Published: Feb 24, 2026Updated: Feb 25, 2026 Sources: CVE List NVDCWE-20
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.5%
Top 61.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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 Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-20

Affected Products

udmfree5gc
Mixed
Networking Infrastructure / network-management
free5gcoss-projectNetworking Infrastructureaka free5gc udm, free5gc smf, udm, smf

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Initial Access
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References

https://github.com/free5gc/free5gc/security/advisories/GHSA-h4wg-rp7m-8xx4
github.com
https://github.com/free5gc/free5gc/issues/749
github.com
https://github.com/free5gc/udm/pull/75
github.com
and 1 more references View all →

Timeline

Published
Feb 24, 2026
Last Updated
Feb 25, 2026

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