---
title: "CVE-2026-44329: free5GC's SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers"
url: https://erroneo.us/security/cve/CVE-2026-44329/
description: "CVE-2026-44329 (github.com/free5gc/smf (Go)): free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's SMF mounts the UPI…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-27
date_modified: 2026-06-08
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-44329"
kev: false
cvss: 10
epss: 0.00563
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-44329: free5GC's SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.6% , percentile 46: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 46% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/free5gc/smf (Go) < 1.4.3, fixed in 1.4.3 . Check your lockfile, including transitive dependencies.

## What it is

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 OAuth2/bearer-token authorization middleware. A network attacker who can reach SMF on the SBI can hit UPI endpoints with no Authorization header at all, and the requests reach the SMF business handlers. In the running Docker lab this was directly demonstrated for read (GET /upi/v1/upNodesLinks), write (POST /upi/v1/upNodesLinks with attacker-controlled UP-node and link payload), and delete (DELETE /upi/v1/upNodesLinks/{nodeID}) operations. This vulnerability is fixed in 4.2.2.

## Affected packages

- Go `github.com/free5gc/smf` < 1.4.3 → fixed: 1.4.3

## Affected products (CVE record)

- free5gc free5gc: < 4.2.2

## Severity

- GitHub_M CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H`
- GitHub CVSS 3.1: 10.0 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.56% probability of exploitation activity in the next 30 days; percentile 46.

## Sources

- [GitHub Advisory GHSA-3258-qmv8-frp3](https://github.com/advisories/GHSA-3258-qmv8-frp3)
- [CVE.org record CVE-2026-44329](https://www.cve.org/CVERecord?id=CVE-2026-44329)
- [NVD entry CVE-2026-44329](https://nvd.nist.gov/vuln/detail/CVE-2026-44329)
- [github.com](https://github.com/free5gc/free5gc/security/advisories/GHSA-3258-qmv8-frp3)
- [github.com](https://github.com/free5gc/free5gc/issues/887)
- [github.com](https://github.com/free5gc/smf/pull/197)
- [github.com](https://github.com/free5gc/smf/commit/e23ce97565f285eb99eed153743c62bf4c767c6e)

---
Source page: https://erroneo.us/security/cve/CVE-2026-44329/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt