CVE-2026-42081
Free5Gc ≤ 4.2.2
Raw vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:LCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
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 Downgrade Attack (T1689); ranked at the 18th 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 Data
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…
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§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 Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V17.2.8
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.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require correct implementation of standardized security checks and algorithms.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development and acceptance validates that required security checks function as specified.
Use of cryptography control depends on correct implementation of standardized cryptographic checks.
Secure development life cycle mandates verification that security checks required by standards are correctly implemented.
Application security requirements explicitly call for correct implementation of standardized security mechanisms.
Secure system architecture and engineering principles require faithful realization of protocol-level security checks.
Secure coding practices directly address correct implementation of security-relevant checks in standardized algorithms.