CVE-2026-44327

CRITICAL EPSS 22.8%
Published May 27, 20261mo ago · Modified Jun 17, 20262w ago
10.0 CVSS 3.1
Critical
Find Similar
Published May 27, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
10.0
Exploitability
3.9
Impact
6.0
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Changed
Confidentiality Low
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
22.8% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 2

CWE-306 Missing Authentication for Critical Function Authentication
CWE-862 Missing Authorization Authorization

Affected Products 1

VendorProductVersionRange
free5gcfree5gc* <4.2.2

References 3

  • github.com https://github.com/free5gc/free5gc/issues/861
    ExploitIssue Tracking
  • github.com https://github.com/free5gc/free5gc/security/advisories/GHSA-cmpj-2x3g-m7g3
    ExploitVendor Advisory
  • github.com https://github.com/free5gc/nef/pull/23
    Issue TrackingPatch

Remediation

  • github.com https://github.com/free5gc/nef/pull/23
    Issue TrackingPatch