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CVE-2026-44321

Free5gc authentication bypass

7.5 HIGHPublic exploitEPSS 0.61%
  1. Published27 May 2026

Description

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's SMF mounts the UPI management route group without inbound OAuth2 middleware. The POST /upi/v1/upNodesLinks create-or-update handler accepts attacker-controlled JSON and passes it directly into UpNodesFromConfiguration(), which calls logger.InitLog.Fatalf(...) on several validation failures. One confirmed path is the UE-IP-pool overlap check: a single unauthenticated POST that adds a new UPF whose pool overlaps an existing UPF terminates the entire SMF process (docker ps shows Exited (1)), not just the goroutine. This vulnerability is fixed in 4.2.2.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Free5gc< 4.2.2

Remediation

Fixed in
Free5gc≥ 4.2.2

References

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Frequently asked

Is CVE-2026-44321 being actively exploited?

CVE-2026-44321 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.61%.

How severe is CVE-2026-44321?

CVE-2026-44321 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.61% probability of exploitation.

Which products are affected by CVE-2026-44321?

Affected products include Free5gc.

How do I fix CVE-2026-44321?

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-2026-44321 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.