CVE-2026-40343
Fail-Open Request Handling Flaw in free5GC UDR Service
Publication date: 2026-04-22
Last updated on: 2026-04-23
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| free5gc | free5gc | to 4.2.1 (inc) |
| free5gc | udr | to 1.4.2 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-754 | The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
The vulnerability exists in free5GC UDR, the user data repository component of the free5GC open-source 5G core network project. In versions up to and including 1.4.2, there is a fail-open flaw in the handling of POST requests to the /nudr-dr/v2/policy-data/subs-to-notify endpoint. Specifically, even if there are errors retrieving or deserializing the request body, the service continues processing the request. This can lead to the unintended creation of Policy Data notification subscriptions with invalid, empty, or partially processed input, depending on how downstream processors handle the data.
How can this vulnerability impact me? :
This vulnerability can impact you by allowing the creation of invalid or malformed Policy Data notification subscriptions within the free5GC UDR service. Such unintended subscriptions could cause incorrect or unexpected behavior in the 5G core network's policy management functions, potentially leading to service disruptions, incorrect policy enforcement, or other operational issues depending on how downstream components process these invalid subscriptions.
What immediate steps should I take to mitigate this vulnerability?
As of the time of publication, a patched version of free5GC UDR is not available.
Immediate mitigation steps are not specified in the provided information.