PatchTheCVECVE-2026-42081: free5GC is an open-source implementation of the 5G core network
CVE-2026-42081 is a medium-severity flaw (CVSS 6.1) affecting free5gc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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
Why this priority
- Public exploit reference
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.1 (Medium) |
| Attack vector | Adjacent network |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.3% (top 81%) |
| CISA exploited list | No |
| Weakness | CWE-358 |
| Published | 2026-05-27 |
| Last modified | 2026-10-14 |
Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-42081?
free5gc: upgrade to 4.2.2. Exact commands for each OS are on this page.
Is CVE-2026-42081 being exploited?
CVE-2026-42081 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-42081 affect?
CVE-2026-42081 affects free5gc. Severity is medium (CVSS 6.1). 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 3
How urgent is CVE-2026-42081?
Priority 31/100. Public exploit reference
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