# CVE-2026-44328: free5GC SMF unauthenticated DoS and state mutation in UPI handler

Source: https://junglewise.ai/threats/cve-2026-44328-free5gc-smf-unauthenticated-dos-and-state-mutation-in-upi-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-27. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-44328 · Severity: high · CVSS 8.2 · Published 2026-05-27

A vulnerability in the free5GC Session Management Function (SMF) allows an unauthenticated attacker to delete critical network nodes from the system's memory. The SMF is a core component of 5G networks responsible for managing user sessions; by exploiting this flaw, an attacker can disrupt network connectivity and cause the management service to crash. This can lead to a denial of service for mobile users and require manual intervention to restore the network's topology.

Technologies: [free5GC Smf](https://junglewise.ai/threats/technologies/smf), [github.com/free5gc/smf (Go)](https://junglewise.ai/threats/technologies/github-com-free5gc-smf). Vendors: [free5GC](https://junglewise.ai/threats/vendors/free5gc), [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-44328 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-44328 being exploited in the wild.

**How severe is CVE-2026-44328?** High severity, with a CVSS score of 8.2, published 27 May 2026.

**Which products and versions are affected?** free5GC Smf < 1.4.3, <= 4.2.1; github.com/free5gc/smf (Go) < 1.4.3, SEMVER:introduced=0,fixed=1.4.3.

**Is there a fix for CVE-2026-44328?** Yes. github.com/free5gc/smf (Go): upgrade to 1.4.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-44328 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-44328?** Check whether you run free5GC Smf or github.com/free5gc/smf (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/free5gc/smf (Go): upgrade to 1.4.3 or later

  ```sh
  go get github.com/free5gc/smf@v1.4.3
  ```


## Technical details

The free5GC SMF UPI management route group is mounted without OAuth2 authentication middleware, making its endpoints reachable unauthenticated. In the 'DELETE /upi/v1/upNodesLinks/{ref}' handler, the code unconditionally dereferences the 'UPF' field of a node object. However, Access Network (AN) nodes are constructed with a nil 'UPF' field, leading to a nil pointer dereference and a panic. Crucially, the 'UpNodeDelete' function is called before the panic occurs, meaning the in-memory user-plane topology is mutated (nodes are deleted) even if the request fails. This allows an off-path network attacker to persistently deny SMF's ability to establish PFCP paths for UE sessions. The issue is fixed in SMF version 1.4.3.

## Affected products

- free5GC SMF < 1.4.3

## Identifiers

- CVE-2026-44328
- GHSA-p9mg-74mg-cwwr
- GO-2026-5537

## Timeline

- 2026-05-07: disclosed
- 2026-05-08: advisory: GitHub Advisory published
- 2026-05-27: other: NVD published

## References

- [https://api.github.com/users/LinZiyuu](https://api.github.com/users/LinZiyuu)
- [https://github.com/LinZiyuu](https://github.com/LinZiyuu)
- [https://api.github.com/users/LinZiyuu/gists%7B/gist_id%7D](https://api.github.com/users/LinZiyuu/gists%7B/gist_id%7D)
- [https://api.github.com/users/LinZiyuu/repos](https://api.github.com/users/LinZiyuu/repos)
- [https://avatars.githubusercontent.com/u/104151270?v=4](https://avatars.githubusercontent.com/u/104151270?v=4)
- [https://api.github.com/users/LinZiyuu/events%7B/privacy%7D](https://api.github.com/users/LinZiyuu/events%7B/privacy%7D)

## Related threats

- [free5GC SMF missing authentication in UPI management interface](https://junglewise.ai/threats/cve-2026-44329-free5gc-smf-missing-authentication-in-upi-management-interface)
- [free5GC SMF unauthenticated denial of service in UPI management](https://junglewise.ai/threats/cve-2026-44321-free5gc-smf-unauthenticated-denial-of-service-in-upi-management)