CVE-2026-42081
Published: 27 May 2026
Summary
CVE-2026-42081 is a medium-severity Improperly Implemented Security Check for Standard (CWE-358) vulnerability in Free5Gc Free5Gc. Its CVSS base score is 6.1 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 7.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-32557
Vulnerability details
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…
more
§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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability enables crafted remote messages from gNB to AMF resulting in targeted denial of service via application logic exploitation.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Assessments identify and document improperly implemented security checks, allowing fixes that reduce exploitation of flawed checks.