CVE-2026-44327

free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler

Published May 27, 2026 CVSS 3.1 · 10 Critical EPSS < 1% KEV · Not listed
Description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the nnef-oam route group without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can hit the OAM route with no Authorization header at all and the handler returns 200 OK. The current OAM handler is a stub that returns null, but the structural defect is route-group-scoped: the entire OAM route group has no inbound auth middleware, so every future OAM operation added to this group inherits the missing auth boundary by default. This vulnerability is fixed in 4.2.2.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-cmpj-2x3g-m7g3 free5GC's NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler
History
Type Values Removed Values Added
CPEs cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Free5gc
Free5gc free5gc
Vendors & Products Free5gc
Free5gc free5gc
Type Values Removed Values Added
Description free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the nnef-oam route group without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can hit the OAM route with no Authorization header at all and the handler returns 200 OK. The current OAM handler is a stub that returns null, but the structural defect is route-group-scoped: the entire OAM route group has no inbound auth middleware, so every future OAM operation added to this group inherits the missing auth boundary by default. This vulnerability is fixed in 4.2.2.
Title free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler
Weaknesses CWE-306
CWE-862
References
Metrics cvssV3_1

{'score': 10, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 28, 2026, 2:40 PM
Reserved
May 5, 2026, 7:00 PM
Status
Analyzed
Published
May 27, 2026, 5:16 PM
Modified
Oct 14, 2026, 8:10 PM