Critical severity · published May 27, 2026
CVE-2026-44329
free5GC: SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers
10.0
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 26% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
free5gc · free5gc
< 4.2.2 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44329
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-44329
Exploit
https://github.com/free5gc/free5gc/issues/887
Exploit
https://github.com/free5gc/free5gc/security/advisories/GHSA-3258-qmv8-frp3
Patch
https://github.com/free5gc/smf/commit/e23ce97565f285eb99eed153743c62bf4c767c6e
Issue Tracking
https://github.com/free5gc/smf/pull/197
More from free5gc
10.0
CVE-2026-44327
free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler
10.0
CVE-2026-44330
free5GC: NEF nnef-pfdmanagement API is unauthenticated; forged bearer tokens can read PFD data and create/delete PFD subscriptions
9.4
CVE-2026-44315
free5GC: NEF 3gpp-pfd-management API is unauthenticated; forged bearer tokens can create, read, and delete PFD transactions
9.4
CVE-2026-44326
free5GC: NEF 3gpp-traffic-influence API is unauthenticated; missing or forged bearer tokens can create, read, patch, and delete subscriptions
9.3
CVE-2026-55068
free5GC: NRF nnrf-nfm lacks NF Profile input validation — enables NF Registration Poisoning with arbitrary service endpoints