# CVE-2026-42082: free5GC AMF improper security check in concurrent procedures

Source: https://junglewise.ai/threats/cve-2026-42082-free5gc-amf-improper-security-check-in-concurrent-procedures  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-27. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-42082 · Severity: low · CVSS 3.7 · Published 2026-05-27

A vulnerability exists in the Free5GC Access and Mobility Management Function (AMF), which manages mobile device connections in a 5G network. The system fails to properly coordinate security updates and network handovers when they happen at the same time. This can cause a mismatch in security keys between the mobile device and the network, potentially leading to dropped connections or failed handovers.

Technologies: [github.com/free5gc/amf (Go)](https://junglewise.ai/threats/technologies/github-com-free5gc-amf). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-42082 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42082 being exploited in the wild.

**How severe is CVE-2026-42082?** Low severity, with a CVSS score of 3.7, published 27 May 2026.

**Which products and versions are affected?** github.com/free5gc/amf (Go) <= 1.4.3, SEMVER:introduced=0, SEMVER:introduced=0,last_affected=1.4.3.

**Is there a fix for CVE-2026-42082?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-42082 attacked?** It is attacked from the adjacent network, in a hosted service.

**Am I affected by CVE-2026-42082?** Check whether you run github.com/free5gc/amf (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The Free5GC AMF implementation of the Access and Mobility Management Function (AMF) violates 3GPP TS 33.501 §6.9.5.1 by failing to implement cross-procedure validation between NAS Security Mode Command (SMC) and N2 handover procedures. Specifically, the 'SecurityMode()' function in 'internal/gmm/sm.go' initiates an SMC without checking for ongoing N2 handovers, and 'handleHandoverRequiredMain()' in 'internal/ngap/handler.go' initiates handovers without checking for ongoing SMCs. Because SMC activates a new KAMF key while N2 handovers rely on NH/NCC derived from the previous key, concurrent execution causes the target gNB and the User Equipment (UE) to derive different KgNB keys. This results in an Access Stratum (AS) security context mismatch, impacting connection integrity and availability.

## Affected products

- Free5GC AMF <= 1.4.3

## Identifiers

- CVE-2026-42082
- GHSA-vrrx-58h3-prmh
- GO-2026-5673

## Timeline

- 2026-05-07: advisory: GitHub Advisory GHSA-vrrx-58h3-prmh published
- 2026-05-27: disclosed: NVD publication date

## References

- [https://api.github.com/users/SJNA0414](https://api.github.com/users/SJNA0414)
- [https://github.com/SJNA0414](https://github.com/SJNA0414)
- [https://api.github.com/users/SJNA0414/gists%7B/gist_id%7D](https://api.github.com/users/SJNA0414/gists%7B/gist_id%7D)
- [https://api.github.com/users/SJNA0414/repos](https://api.github.com/users/SJNA0414/repos)
- [https://avatars.githubusercontent.com/u/197385222?v=4](https://avatars.githubusercontent.com/u/197385222?v=4)
- [https://api.github.com/users/SJNA0414/events%7B/privacy%7D](https://api.github.com/users/SJNA0414/events%7B/privacy%7D)

## Related threats

- [GO-2026-5767 - Free5GC AMF is vulnerable to DoS through its HandleRegistrationComplete function in github.com/free5gc/amf](https://junglewise.ai/threats/cve-2026-4531-free5gc-amf-is-vulnerable-to-dos-through-its)
- [free5GC AMF improper security check in NGAP PathSwitchRequest](https://junglewise.ai/threats/cve-2026-42081-free5gc-amf-improper-security-check-in-ngap-pathswitchrequest)
- [free5GC AMF: Missing default case in Content-Type switch in HTTPUEContextTransfer](https://junglewise.ai/threats/cve-2026-41136-free5gc-amf-missing-default-case-in-content-type-switch-in)
- [free5GC AMF denial of service vulnerability](https://junglewise.ai/threats/cve-2023-49391-free5gc-amf-denial-of-service-vulnerability)