Free5GC up to 1.4.1 AUSF Service ue-authentications GetSupiFromSuciSupiMap null pointer dereference

Summaryinfo

A vulnerability was found in Free5GC up to 1.4.1. It has been rated as problematic. This vulnerability affects the function GetSupiFromSuciSupiMap of the file /nausf-auth/v1/ue-authentications of the component AUSF Service. The manipulation leads to null pointer dereference. This vulnerability is uniquely identified as CVE-2026-33063. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Free5GC up to 1.4.1. It has been rated as problematic. This issue affects the function GetSupiFromSuciSupiMap of the file /nausf-auth/v1/ue-authentications of the component AUSF Service. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

free5GC is an open source 5G core network. free5GC AUSF prior to version 1.4.2 has is an Improper Null Check vulnerability leading to Denial of Service. All deployments of free5GC v4.0.1 using the AUSF UE authentication service (`/nausf-auth/v1/ue-authentications` endpoint) are affected. A remote attacker can cause the AUSF service to panic and crash by sending a crafted UE authentication request that triggers a nil interface conversion in the `GetSupiFromSuciSupiMap` function. This results in complete denial of service for the AUSF authentication service. The `GetSupiFromSuciSupiMap` function attempts to perform an interface conversion from `interface{}` to `*context.SuciSupiMap` without checking if the underlying value is nil. When `SuciSupiMap` is nil, the code panics with "interface conversion: interface {} is nil, not *context.SuciSupiMap". free5GC AUSF version 1.4.2 patches the issue. There is no direct workaround at the application level. The recommendation is to apply the provided patch or restrict access to the AUSF API to trusted sources only.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-33063 since 03/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 1.4.2 eliminates this vulnerability. Applying the patch 3b9ac4403c2756dc89a5ed3cdcefe688458588aa is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Name

• Free5GC

Version

• 1.4.0
• 1.4.1

License

• open-source

Website

• Product: https://github.com/free5gc/free5gc/

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