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CVE-2026-44327

Free5gc authentication bypass

10.0 CRITICALPublic exploitEPSS 0.53%
  1. Published27 May 2026

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 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeChanged
ConfidentialityLow
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H

Affected products

Free5gc< 4.2.2

Remediation

Fixed in
Free5gc≥ 4.2.2

References

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Frequently asked

Is CVE-2026-44327 being actively exploited?

CVE-2026-44327 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.53%.

How severe is CVE-2026-44327?

CVE-2026-44327 has a CVSS 3.1 base score of 10.0, rated critical. EPSS estimates a 0.53% probability of exploitation.

Which products are affected by CVE-2026-44327?

Affected products include Free5gc.

How do I fix CVE-2026-44327?

Upgrade affected software to a fixed version, for example Free5gc 4.2.2 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-44327 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.