Free5GC up to 4.2.1 /upi/v1/upNodesLinks/ missing authentication

Summaryinfo

A vulnerability described as critical has been identified in Free5GC up to 4.2.1. Impacted is an unknown function of the file /upi/v1/upNodesLinks/. Executing a manipulation can lead to missing authentication. This vulnerability appears as CVE-2026-44328. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Free5GC up to 4.2.1 and classified as critical. This vulnerability affects an unknown code block of the file /upi/v1/upNodesLinks/. The manipulation with an unknown input leads to a missing authentication vulnerability. The CWE definition for the vulnerability is CWE-306. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. As an impact it is known to affect integrity, and availability. CVE summarizes:

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 inbound OAuth2 middleware. On top of that, the DELETE /upi/v1/upNodesLinks/{upNodeRef} handler unconditionally dereferences upNode.UPF after the type-guarded async release, even though AN-typed nodes are constructed without a UPF object. As a result, a single unauthenticated DELETE /upi/v1/upNodesLinks/gNB1 request crashes the handler with a nil-pointer panic AND mutates the in-memory user-plane topology before panicking (the UpNodeDelete(upNodeRef) line runs first). This is an unauthenticated, state-mutating panic-DoS sink that an off-path network attacker can trigger by name against any AN entry. This vulnerability is fixed in 4.2.2.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-44328 since 05/05/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

Upgrading to version 4.2.2 eliminates this vulnerability.

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Productinfo

Name

• Free5GC

Version

• 4.2.0
• 4.2.1

Website

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

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