Summary
Impact
This is an Improper Error Handling vulnerability with Information Exposure implications.
- Security Impact: The UDM incorrectly converts a downstream 400 Bad Request (from UDR) into a 500 Internal Server Error when handling DELETE requests with an empty
supipath parameter. This leaks internal error handling behavior and makes it difficult for clients to distinguish between client-side errors and server-side failures. - Functional Impact: When a client sends a DELETE request with an empty
supi(e.g., double slashes//in URL path), the UDM forwards the malformed request to UDR, which correctly returns 400. However, UDM propagates this as 500 SYSTEM_FAILURE instead of returning the appropriate 400 error to the client. This violates REST API best practices for DELETE operations. - Affected Parties: All deployments of free5GC v4.0.1 using the UDM Nudm_SDM service with DELETE operations on sdm-subscriptions endpoint.
Patches
Yes, the issue has been patched.
The fix is implemented in PR free5gc/udm#79.
Users should upgrade to the next release of free5GC that includes this commit.
Workarounds
There is no direct workaround at the application level. The recommendation is to apply the provided patch or implement API gateway-level validation to reject DELETE requests with empty path parameters before they reach UDM.
Impact
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-2026-33065? CVE-2026-33065 is a medium-severity security vulnerability in github.com/free5gc/udm (go), affecting versions < 1.4.2. It is fixed in 1.4.2.
- Which versions of github.com/free5gc/udm are affected by CVE-2026-33065? github.com/free5gc/udm (go) versions < 1.4.2 is affected.
- Is there a fix for CVE-2026-33065? Yes. CVE-2026-33065 is fixed in 1.4.2. Upgrade to this version or later.
- Is CVE-2026-33065 exploitable, and should I be worried? Whether CVE-2026-33065 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-2026-33065 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-2026-33065? Upgrade
github.com/free5gc/udmto 1.4.2 or later.