Free5GC up to 4.2.1 NAS Security Mode security check

CVSS Meta Temp Score
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CTI Interest Score
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3.7$0-$5k0.00

Summaryinfo

A vulnerability was found in Free5GC up to 4.2.1. It has been rated as problematic. The impacted element is an unknown function of the component NAS Security Mode. This manipulation causes security check. This vulnerability appears as CVE-2026-42082. The attacker needs to be present on the local network. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic was found in Free5GC up to 4.2.1. Affected by this vulnerability is an unknown function of the component NAS Security Mode. The manipulation with an unknown input leads to a security check vulnerability. The CWE definition for the vulnerability is CWE-358. The product does not implement or incorrectly implements one or more security-relevant checks as specified by the design of a standardized algorithm, protocol, or technique. As an impact it is known to affect integrity, and availability. The summary by CVE is:

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, the AMF in Free5GC does not enforce the concurrent security procedure rules defined in 3GPP TS 33.501 §6.9.5.1. The AMF does not check for ongoing N2 handover procedures before initiating a NAS Security Mode Command, and vice versa. This can lead to mismatches between NAS and AS security contexts in the network and the UE. This vulnerability is fixed in 4.2.2.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-42082 since 04/23/2026. The exploitation appears to be difficult. The attack needs to approached within the local network. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1211 for this issue.

Upgrading to version 4.2.2 eliminates this vulnerability.

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Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.7

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 3.7
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Security check
CWE: CWE-358
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Free5GC 4.2.2

Timelineinfo

04/23/2026 CVE reserved
05/27/2026 +34 days Advisory disclosed
05/27/2026 +0 days VulDB entry created
05/27/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-42082 (🔒)
GCVE (CVE): GCVE-0-2026-42082
GCVE (VulDB): GCVE-100-366373

Entryinfo

Created: 05/27/2026 18:47
Changes: 05/27/2026 18:47 (62)
Complete: 🔍
Cache ID: 216::103

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