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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Free5gc Free5gc
cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*
|
— |
4.2.2
|
References 4
https://github.com/free5gc/free5gc/issues/887
security-advisories@github.com
https://github.com/free5gc/free5gc/security/advisories/GHSA-3258-qmv8-frp3
security-advisories@github.com
https://github.com/free5gc/smf/commit/e23ce97565f285eb99eed153743c62bf4c767c6e
security-advisories@github.com
https://github.com/free5gc/smf/pull/197
security-advisories@github.com