{"id":"CVE-2026-48599","aliases":["EEF-CVE-2026-48599","GHSA-mwr4-5g34-j5cq"],"url":"https://o3.security/vulnerability/CVE-2026-48599","summary":"Authorization bypass via path binding override in elixir-grpc/grpc HTTP transcoding","details":"Authorization Bypass Through User-Controlled Key vulnerability in elixir-grpc grpc allows authenticated attackers to access or modify resources belonging to other users by smuggling a conflicting value for any path-bound field via the query string or request body.\n\nIn 'Elixir.GRPC.Server.Transcode':map_request/5 (lib/grpc/server/transcode.ex), all three clauses use Map.merge/2 with path bindings as the first argument, giving them the lowest merge precedence. A request such as GET /users/me/profile?user_id=victim (or a POST with {\"user_id\": \"victim\"} when body: \"*\") yields a decoded protobuf struct where the path-bound field carries the attacker-supplied value rather than the router-extracted value. Any handler that uses the path-bound field for authorization, multi-tenancy scoping, or ownership checks is silently bypassed.\n\nThis issue affects grpc from 0.8.0 before 1.0.0.","published":"2026-06-15T21:55:28.702Z","modified":"2026-08-12T03:51:09.148288938Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Hex","name":"grpc","fixedVersion":"1.0.0"}],"fix":{"url":"https://github.com/elixir-grpc/grpc/commit/33b6a095dbc91c6dee3c7b90893d7d74952e82e4","label":"elixir-grpc/grpc@33b6a09"},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-48599.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-48599"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48599.json"},{"type":"ADVISORY","url":"https://github.com/elixir-grpc/grpc/security/advisories/GHSA-mwr4-5g34-j5cq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48599"},{"type":"FIX","url":"https://github.com/elixir-grpc/grpc/commit/33b6a095dbc91c6dee3c7b90893d7d74952e82e4"},{"type":"PACKAGE","url":"https://github.com/elixir-grpc/grpc"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:09.148288938Z"}}