Vulnerability · Published May 27, 2026 · Assigned by GitHub_M
CVE-2026-42081free5GC: UE Security Capability bypass on NGAP PathSwitchRequest
Medium 6.1
In plain English
A medium-severity security flaw in free5gc from free5gc. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 19% of all known vulnerabilities).
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/free5gc/amf | no fix listed | GO-2026-5209 |
| Go | github.com/free5gc/amf | no fix listed | GHSA-77x9-rf64-92gv |
Affected products (as reported)
Weakness: CWE-358 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L
References
- https://github.com/free5gc/free5gc/security/advisories/GHSA-77x9-rf64-92gv x_refsource_CONFIRM