CVE-2026-33065
This leaks internal error handling behavior and makes it difficult for clients to distinguish between client-side errors and server-side failures.
Does this matter?
Lower severity and a low EPSS score (0.28%). Track it; it rarely justifies an emergency change on its own.
Description
Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. In versions prior to 1.4.2, the UDM incorrectly converts a downstream 400 Bad Request (from UDR) into a 500 Internal Server Error when handling DELETE requests with an empty supi path parameter. This leaks internal error handling behavior and makes it difficult for clients to distinguish between client-side errors and server-side failures. 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. The issue has been patched in version 1.4.2.
- CVSS 4.0
- 6.9 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.28% probability · 21th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-209
- Affected
- free5gc/udm
- Source
- security-advisories@github.com
References
- https://github.com/free5gc/free5gc/issues/783Exploit, Issue Tracking, Patch, Vendor Advisory
- https://github.com/free5gc/free5gc/security/advisories/GHSA-958m-gxmc-mccmPatch, Vendor Advisory
- https://github.com/free5gc/udm/commit/88de9fa74a1b3f3522e53b4cfa2d184712ffa4eePatch
- https://github.com/free5gc/udm/pull/79Issue Tracking, Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.