CVE-2026-44324

free5GC's UDR nudr-dr DELETE amf-subscriptions panics on missing UE state via nil interface type assertion (single authenticated request)

Incorrect type conversion on a nil interface (CWE-704) inside an authenticated UDR data-repository handler, caused by improper handling of the missing-ueId branch (CWE-754): the handler sets a 404 problem-details value but does not return, then runs a Go type assertion on the nil interface returned by sync.Map.Load.

This is NOT framed as an auth-bypass finding: the endpoint requires a valid nudr-dr OAuth2 access token. A network attacker who already holds (or can obtain) a valid token can:

• Trigger a reliable, single-request panic on the amf-subscriptions delete route against a fresh UDR (no preparatory state needed -- this is strictly easier than free5gc/free5gc#919).
• Repeat the trigger to sustain a per-request panic-DoS on UDR's data-repository surface, with each panic costing more CPU + log writes than the intended 404 USER_NOT_FOUND response would have.

No Confidentiality impact (the response is 500 with empty body). No Integrity impact (the panic happens before any state mutation). Availability impact is limited to per-request degradation (Gin recovers; the UDR process keeps running).

Affected: free5gc v4.2.1.

Upstream issue: https://github.com/free5gc/free5gc/issues/920
Upstream fix: https://github.com/free5gc/udr/pull/60

CVE-2026-44324 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low 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.

Kodem intelligence

1. What is CVE-2026-44324? CVE-2026-44324 is a medium-severity security vulnerability in github.com/free5gc/udr (go), affecting versions < 1.4.3. It is fixed in 1.4.3.
2. How severe is CVE-2026-44324? CVE-2026-44324 has a CVSS score of 6.5 (Medium). 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.
3. Which versions of github.com/free5gc/udr are affected by CVE-2026-44324? github.com/free5gc/udr (go) versions < 1.4.3 is affected.
4. Is there a fix for CVE-2026-44324? Yes. CVE-2026-44324 is fixed in 1.4.3. Upgrade to this version or later.
5. Is CVE-2026-44324 exploitable, and should I be worried? Whether CVE-2026-44324 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
6. What actually determines whether CVE-2026-44324 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.
7. How do I fix CVE-2026-44324? Upgrade github.com/free5gc/udr to 1.4.3 or later.