CVE-2026-42083
Published: 27 May 2026
Summary
CVE-2026-42083 is a high-severity Missing Authorization (CWE-862) vulnerability in Free5Gc Free5Gc. Its CVSS base score is 8.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 16.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
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.
Requiring an access control policy ensures authorization checks are defined and applied for critical functions.
Reviews of access controls detect missing authorization checks on critical functions or resources.
Documenting permitted unauthenticated actions prevents missing authorization by making all exceptions explicit and subject to organizational review.
Requiring attribute association with information prevents authorization from being performed without necessary security or privacy context.
Mandating authorization prior to allowing remote connections addresses missing authorization for remote access.
Mandating authorization before wireless connections are allowed prevents missing authorization for wireless access.
The control requires authorization before allowing mobile device connections, directly mitigating missing authorization for system access.
Requiring approvals for account creation and specifying authorizations ensures authorization is not missing for system access.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Missing authentication middleware on exposed PCF SM policy endpoints directly enables exploitation of a public-facing 5G network application (T1190).
NVD Description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, PCF Npcf_SMPolicyControl missing authentication middleware allows unauthenticated access to SM policy handlers and disclosure of subscriber SUPI. In NewServer(), the smPolicyGroup route group is created and routes…
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are applied without attaching the router authorization middleware. In contrast, other PCF service groups such as Npcf_PolicyAuthorization do attach RouterAuthorizationCheck before route registration. Because the middleware is missing, requests to the /npcf-smpolicycontrol/v1/sm-policies, /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}, /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/update, and /npcf-smpolicycontrol/v1/sm-policies/{smPolicyId}/delete endpoints can reach business logic even when no valid OAuth token is provided. This vulnerability is fixed in 4.2.2.
Deeper analysisAI
Automated synthesis unavailable for this CVE.
Details
- CWE(s)
- OWASP Top 10 Web 2025
Affected Products
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-32555