# CVE-2026-44323: free5GC UDR nil pointer dereference in nudr-dr DELETE handler

Source: https://junglewise.ai/threats/cve-2026-44323-free5gc-udr-nil-pointer-dereference-in-nudr-dr-delete-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-2026-44323 · Severity: medium · CVSS 4.3 · Published 2026-05-27

A vulnerability exists in free5GC's Unified Data Repository (UDR), a component used in 5G core networks to manage subscriber data. An authenticated user can cause the service to crash or return error messages by sending a specifically crafted request to delete subscription data that does not exist. While the system automatically recovers from each crash, a repeated attack could degrade the performance and availability of the subscriber database.

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

## Quick answers

**Is CVE-2026-44323 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-44323 being exploited in the wild.

**How severe is CVE-2026-44323?** Medium severity, with a CVSS score of 4.3, published 27 May 2026.

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

**Is there a fix for CVE-2026-44323?** Yes. github.com/free5gc/udr (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-2026-44323 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-44323?** Check whether you run free5GC Udr or github.com/free5gc/udr (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/udr (Go): upgrade to 1.4.3 or later

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


## Technical details

A NULL pointer dereference (CWE-476) exists in the free5GC UDR 'nudr-dr' service within the 'RemoveAmfSubscriptionsInfoProcedure' handler. The vulnerability is triggered when a DELETE request is made to the '/subscription-data/{ueId}/{servingPlmnId}/ee-subscriptions/{subsId}/amf-subscriptions' endpoint with a non-existent 'subsId' after UE state has been initialized. The code identifies the missing subscription and prepares a 404 error but fails to return, subsequently attempting to access a member of the nil subscription object. This results in a panic that is caught by the Gin recovery middleware, returning an HTTP 500 error. An attacker with a valid OAuth2 access token can repeatedly trigger this panic to cause a denial-of-service. The issue is fixed in version 1.4.3.

## Affected products

- free5GC udr < 1.4.3

## Identifiers

- CVE-2026-44323
- GHSA-4rqf-grm6-vf75
- GO-2026-5131

## Timeline

- 2026-03-22: other: Vulnerability validated in lab environment
- 2026-05-08: advisory: GitHub Advisory published
- 2026-05-27: other: NVD published CVE-2026-44323

## 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 UDR improper input validation in EE subscription handlers](https://junglewise.ai/threats/cve-2026-47780-free5gc-udr-improper-input-validation-in-ee-subscription-handlers)
- [free5GC UDR denial of service via nil type assertion](https://junglewise.ai/threats/cve-2026-44324-free5gc-udr-denial-of-service-via-nil-type-assertion)
- [free5GC UDR: Fail-open handling in PolicyDataSubsToNotifyPost allows unintended subscription creation](https://junglewise.ai/threats/cve-2026-40343-free5gc-udr-fail-open-handling-in-policydatasubstonotifypost)
- [free5gc UDR improper path validation allows unauthenticated deletion of Traffic Influence Subscriptions](https://junglewise.ai/threats/cve-2026-40246-free5gc-udr-improper-path-validation-allows-unauthenticated)
- [free5gc UDR fail-open request handling in PolicyDataSubsToNotifySubsIdPut may allow unintended subscription updates…](https://junglewise.ai/threats/cve-2026-40249-free5gc-udr-fail-open-request-handling-in)