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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-44321: 0.36% estimated exploitation activity in the next 30 days; percentile 30.31 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary free5GC's SMF mounts the UPI management route group without inbound OAuth2 middleware (same root cause as free5gc/free5gc#887). 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 is a stronger sink than free5gc/free5gc#905: that one panics inside the request goroutine and Gin recovers; this one calls Fatalf which is os.Exit(1)-equivalent and kills the whole SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy lookups, etc.) until the process is restarted. Details Validated against the SMF container in the official Docker compose lab. - Source repo tag:…

Published by the source

8 May 2026, 22:47 UTC

Last modified by the source

8 Jun 2026, 23:47 UTC

Source last checked

26 Oct 2026, 15:23 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-44qj-cghf-9p97

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# Patch Next advisory brief: CVE-2026-44321

Advisory: free5GC's SMF UPI POST /upi/v1/upNodesLinks exits the SMF process on overlapping UE pools (unauthenticated, reachable Fatalf)
IDs: CVE-2026-44321, GHSA-44qj-cghf-9p97
Record: https://patchnext.com/advisories/cve-2026-44321 (revision 1, source checked 26 Oct 2026, 15:23 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/free5gc/smf: affected <= 1.4.3

## Suggested inspection (read-only)
- Go github.com/free5gc/smf: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/free5gc/smf.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-44qj-cghf-9p97 (GitHub-reviewed advisory GHSA-44qj-cghf-9p97 lists affected ranges: Go github.com/free5gc/smf >=0 <=1.4.3)

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