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CVE-2026-42081— free5GC: UE Security Capability bypass on NGAP PathSwitchRequest

Quick assessment

Affected
free5gc free5gc
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

free5GC是free5GC开源的一个第 5 代 (5G) 移动核心网络的开源项目。 free5GC 4.2.2之前版本存在安全漏洞，该漏洞源于AMF未验证NGAP PathSwitchRequest消息中的UE安全能力，可能导致恶意gNB覆盖AMF存储的UE安全能力，造成UE持续切换拒绝服务。

CVSS 6.1 · Medium EPSS 0.28% · P19

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
free5gc free5gc < 4.2.2 affected
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I. Basic Information for CVE-2026-42081

Vulnerability Information
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Vulnerability Title
free5GC: UE Security Capability bypass on NGAP PathSwitchRequest
Source: CVE Program / CVE List V5
Vulnerability Description
free5GC 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
不恰当实现的标准安全检查
Source: CVE Program / CVE List V5
Vulnerability Title
free5GC 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
free5GC是free5GC开源的一个第 5 代 (5G) 移动核心网络的开源项目。 free5GC 4.2.2之前版本存在安全漏洞，该漏洞源于AMF未验证NGAP PathSwitchRequest消息中的UE安全能力，可能导致恶意gNB覆盖AMF存储的UE安全能力，造成UE持续切换拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
free5gc free5gc < 4.2.2 -

II. Public POCs for CVE-2026-42081

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III. Intelligence Information for CVE-2026-42081

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Vendor Advisories for CVE-2026-42081 (1)

Same Patch Batch · free5gc · 2026-05-27 · 20 CVEs total

CVE-2026-44327 10.0 CRITICAL free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM hand
CVE-2026-44330 10.0 CRITICAL free5GC: NEF nnef-pfdmanagement API is unauthenticated; forged bearer tokens can read PFD
CVE-2026-44329 10.0 CRITICAL free5GC: SMF UPI management interface lacks auth middleware; unauthenticated topology read
CVE-2026-44326 9.4 CRITICAL free5GC: NEF 3gpp-traffic-influence API is unauthenticated; missing or forged bearer token
CVE-2026-44315 9.4 CRITICAL free5GC: NEF 3gpp-pfd-management API is unauthenticated; forged bearer tokens can create,
CVE-2026-42083 8.2 HIGH free5GC: PCF Npcf_SMPolicyControl missing authentication middleware allows unauthenticated
CVE-2026-44328 8.2 HIGH free5GC: SMF UPI DELETE /upi/v1/upNodesLinks/{ref} panics on AN-node deletion via nil UPF
CVE-2026-44325 7.5 HIGH free5GC: NRF POST /oauth2/token structured-form parser type-confusion panic family (Reflec
CVE-2026-44322 7.5 HIGH free5GC: NEF 3gpp-pfd-management PATCH applications/{appId} panics on UDR access failure d
CVE-2026-44321 7.5 HIGH free5GC: SMF UPI POST /upi/v1/upNodesLinks exits the SMF process on overlapping UE pools (
CVE-2026-44319 7.5 HIGH free5GC: NEF crashes via logger.Fatal on PFD notification delivery failure (attacker-contr
CVE-2026-44316 7.5 HIGH free5GC: PCF npcf-smpolicycontrol POST /sm-policies panics on downstream UDR/OpenAPI 404 v
CVE-2026-44320 7.3 HIGH free5GC: NEF nnef-callback route group is unauthenticated; forged callback requests are ac
CVE-2026-44324 6.5 MEDIUM free5GC: UDR nudr-dr DELETE amf-subscriptions panics on missing UE state via nil interface
CVE-2026-44317 6.5 MEDIUM free5GC: PCF npcf-policyauthorization POST /app-sessions panics on suppFeat=1 with missing
CVE-2026-44318 6.5 MEDIUM free5GC: BSF concurrent PUT /nbsf-management/v1/subscriptions/{subId} crashes the BSF proc
CVE-2026-44323 4.3 MEDIUM free5GC: UDR nudr-dr DELETE amf-subscriptions panics on missing subsId when UE state exist
CVE-2026-42082 3.7 LOW free5GC: Missing Concurrent NAS SMC Validation During NGAP Handover
CVE-2026-42459 free5GC: Improper Input Validation and Generation of Error Message Containing Sensitive In

IV. Related Vulnerabilities

Same product: free5gc
Same vendor: free5gc
Same weakness: CWE-358

V. Comments for CVE-2026-42081

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