Summary
free5GC's SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers
Impact
Missing inbound authentication (CWE-306) and authorization (CWE-862) on the SMF UPI SBI route group. Severity is scored against the route group's intended capability surface (UP-node and link topology management), which is realized by the demonstrated PoC: an unauthenticated network attacker can already today read SMF's view of the UP-plane topology, inject attacker-controlled UPF nodes and link entries, and target deletions of named entries.
Any party that can reach SMF on the SBI can:
- Read SMF's current UP-node and link topology view anonymously.
- Inject attacker-controlled UPF entries (with attacker-chosen nodeID / addr / S-NSSAI / DNN), poisoning SMF's view of which UPFs serve which slices/DNNs and biasing subsequent UPF selection / PFCP path establishment for legitimate PDU sessions.
- Issue topology delete operations against named UPF entries, denying or disrupting legitimate UPF participation in SMF's selection logic.
The defect is route-group-scoped: there is no auth middleware on the UPI group at all, so every UPI endpoint inside this group inherits the missing inbound auth boundary, and the same-instance OAM control proves this is the UPI mount specifically (not a global SMF config issue).
Affected: free5gc v4.2.1.
Upstream issue: https://github.com/free5gc/free5gc/issues/887
Upstream fix: https://github.com/free5gc/smf/pull/197
A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.
CVE-2026-44329 has a CVSS score of 10.0 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.4.3); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-44329? CVE-2026-44329 is a critical-severity missing authentication for critical function vulnerability in github.com/free5gc/smf (go), affecting versions < 1.4.3. It is fixed in 1.4.3. A critical operation is accessible without requiring any authentication.
- How severe is CVE-2026-44329? CVE-2026-44329 has a CVSS score of 10.0 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/free5gc/smf are affected by CVE-2026-44329? github.com/free5gc/smf (go) versions < 1.4.3 is affected.
- Is there a fix for CVE-2026-44329? Yes. CVE-2026-44329 is fixed in 1.4.3. Upgrade to this version or later.
- Is CVE-2026-44329 exploitable, and should I be worried? Whether CVE-2026-44329 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-44329 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-44329? Upgrade
github.com/free5gc/smfto 1.4.3 or later.