{"schema_version":"1.7.5","id":"GHSA-5rvc-5cwx-g5x8","published":"2026-03-18T20:11:27Z","modified":"2026-03-23T18:56:22.583360Z","aliases":["CVE-2026-33192","GO-2026-4755"],"summary":"free5GC UDM incorrectly returns 500 for empty supi path parameter in PATCH sdm-subscriptions reques","details":"**Impact**  \nThis is an Improper Error Handling vulnerability with Information Exposure implications, combined with an HTTP Method Translation issue.  \n- **Security Impact**: The UDM incorrectly converts a downstream 400 Bad Request (from UDR) into a 500 Internal Server Error when handling PATCH requests with an empty `supi` path parameter. Additionally, the UDM incorrectly translates the PATCH method to PUT when forwarding to UDR, indicating a deeper architectural issue. This leaks internal error handling behavior and makes it difficult for clients to distinguish between client-side errors and server-side failures.  \n- **Functional Impact**: When a client sends a PATCH request with an empty `supi` (e.g., double slashes `//` in URL path), the UDM forwards a PUT request to UDR with the malformed path, 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 PATCH operations and may indicate improper HTTP method handling.  \n- **Affected Parties**: All deployments of free5GC v4.0.1 using the UDM Nudm_SDM service with PATCH operations on sdm-subscriptions endpoint.\n\n**Patches**  \nYes, the issue has been patched.  \nThe fix is implemented in PR free5gc/udm#79.  \nUsers should upgrade to the next release of free5GC that includes this commit.\n\n**Workarounds**  \nThere is no direct workaround at the application level. The recommendation is to apply the provided patch or implement API gateway-level validation to reject PATCH requests with empty path parameters before they reach UDM.","affected":[{"package":{"name":"github.com/free5gc/udm","ecosystem":"Go","purl":"pkg:golang/github.com/free5gc/udm"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.4.2"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-5rvc-5cwx-g5x8/GHSA-5rvc-5cwx-g5x8.json"}}],"references":[{"type":"WEB","url":"https://github.com/free5gc/free5gc/security/advisories/GHSA-5rvc-5cwx-g5x8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33192"},{"type":"WEB","url":"https://github.com/free5gc/free5gc/issues/784"},{"type":"WEB","url":"https://github.com/free5gc/udm/pull/79"},{"type":"PACKAGE","url":"https://github.com/free5gc/udm"}],"database_specific":{"cwe_ids":["CWE-209"],"github_reviewed":true,"github_reviewed_at":"2026-03-18T20:11:27Z","nvd_published_at":"2026-03-20T09:16:16Z","severity":"HIGH"},"severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}