CVE & CISA-KEV Catalog

CVE-2026-44327

CRITICAL
10.0
CVSS v3
NVD

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 v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeChanged

Impact

ConfidentialityLow
IntegrityHigh
AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H

Exploit Intelligence

0.31%probability of exploitation in 30 days
23rdpercentile

Low risk: more likely to be exploited than 23% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-28.