free5GC: UE Security Capability bypass on NGAP PathSwitchRequest

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Summary

CVECVE-2026-42081
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-27 17:16:34 UTC
Updated2026-05-29 19:24:54 UTC
Descriptionfree5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, the AMF in Free5GC does not verify the UE Security Capabilities received in NGAP PathSwitchRequest messages against its locally stored values, as mandated by 3GPP TS 33.501 §6.7.3.1. A malicious gNB can overwrite the AMF's stored UE security capabilities with arbitrary values, which are then propagated in PathSwitchRequest Acknowledge messages and subsequent Handover Request messages. This leads to persistent handover denial-of-service for affected UEs. This vulnerability is fixed in 4.2.2.

Risk And Classification

Primary CVSS: v3.1 7.1 HIGH from [email protected]

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS: 0.000250000 probability, percentile 0.076510000 (date 2026-06-01)

Problem Types: CWE-358 | CWE-358 CWE-358: Improperly Implemented Security Check for Standard

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary7.1HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
3.1[email protected]Secondary6.1MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L
3.1CNADECLARED6.1MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Free5gc Free5gc All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Free5gc Free5gc affected < 4.2.2 Not specified

References

ReferenceSourceLinkTags
github.com/free5gc/free5gc/security/advisories/GHSA-77x9-rf64-92gv 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com Vendor Advisory, Exploit
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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