CVE-2026-44329
CWE-306Published: May 27, 2026· Updated: May 28, 2026
Official Description
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 OAuth2/bearer-token authorization middleware. A network attacker who can reach SMF on the SBI can hit UPI endpoints with no Authorization header at all, and the requests reach the SMF business handlers. In the running Docker lab this was directly demonstrated for read (GET /upi/v1/upNodesLinks), write (POST /upi/v1/upNodesLinks with attacker-controlled UP-node and link payload), and delete (DELETE /upi/v1/upNodesLinks/{nodeID}) operations. This vulnerability is fixed in 4.2.2.
Risk Analysis
This critical vulnerability in free5GC's SMF component allows a network attacker to bypass authorization for UPI management routes. An attacker can perform read, write, and delete operations on UP-node and link payloads without any authorization header, leading to potential network disruption or manipulation. The CVSS score of 10.0 indicates the highest possible severity.
There are currently no public exploits known for this vulnerability. The flaw is remotely exploitable with low attack complexity, meaning an attacker could potentially exploit it over a network without significant effort.
Update free5GC to version 4.2.2 or later to address this authorization bypass. Verify that all SMF UPI management routes enforce proper OAuth2/bearer-token authorization.
Technical Analysis
CVE-2026-44329 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 10.0.
The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (6)
Quick Facts
Related CVEs (CWE-306)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-44329 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts