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CVE-2026-44321

free5GC: SMF UPI POST /upi/v1/upNodesLinks exits the SMF process on overlapping UE pools (unauthenticated, reachable Fatalf)

Published: May 27, 2026Updated: May 28, 2026 Sources: CVE List NVDCWE-306
7.5HIGH
NVD MITRE
EPSS Score
0.4%
Top 70.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-306CWE-617CWE-862

Affected Products

free5gc
oss-projectaka free5gc udm, free5gc smf, udm, smf
free5gcOn-premNetwork Device
Networking Infrastructure / router-switch

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

3 techniques
Impact
Initial Access
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References

https://github.com/free5gc/free5gc/security/advisories/GHSA-44qj-cghf-9p97
github.com
https://github.com/free5gc/free5gc/issues/906
github.com
https://github.com/free5gc/smf/pull/203
github.com
and 1 more references View all →

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