{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-48599: Authorization bypass via path binding override in elixir-grpc/grpc HTTP transcoding","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-48599","status":"final","version":"1","initial_release_date":"2026-06-15T21:55:28.702Z","current_release_date":"2026-06-15T21:55:28.702Z","revision_history":[{"date":"2026-06-15T21:55:28.702Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-48599 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-48599"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-48599"},{"category":"external","summary":"github.com","url":"https://github.com/elixir-grpc/grpc/security/advisories/GHSA-mwr4-5g34-j5cq"},{"category":"external","summary":"cna.erlef.org","url":"https://cna.erlef.org/cves/CVE-2026-48599.html"},{"category":"external","summary":"osv.dev","url":"https://osv.dev/vulnerability/EEF-CVE-2026-48599"},{"category":"external","summary":"github.com","url":"https://github.com/elixir-grpc/grpc/commit/33b6a095dbc91c6dee3c7b90893d7d74952e82e4"}]},"product_tree":{"branches":[{"category":"vendor","name":"elixir-grpc","branches":[{"category":"product_name","name":"grpc","branches":[{"category":"product_version_range","name":">=0.8.0 <1.0.0","product":{"name":"elixir-grpc grpc >=0.8.0 <1.0.0","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:elixir-grpc:grpc:*:*:*:*:*:*:*:*"}}}]}]},{"category":"vendor","name":"elixir-grpc","branches":[{"category":"product_name","name":"grpc","branches":[{"category":"product_version_range","name":">=8aaf3d3a8c4c7b08ac65e9c6f254e0d24da1d048 <33b6a095dbc91c6dee3c7b90893d7d74952e82e4","product":{"name":"elixir-grpc grpc >=8aaf3d3a8c4c7b08ac65e9c6f254e0d24da1d048 <33b6a095dbc91c6dee3c7b90893d7d74952e82e4","product_id":"CSAFPID-2","product_identification_helper":{"cpe":"cpe:2.3:a:elixir-grpc:grpc:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-48599","title":"Authorization bypass via path binding override in elixir-grpc/grpc HTTP transcoding","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1","CSAFPID-2"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","baseScore":7.6,"baseSeverity":"HIGH"},"products":["CSAFPID-1","CSAFPID-2"]}],"remediations":[{"category":"vendor_fix","details":"Update to a fixed version: 1.0.0, 33b6a095dbc91c6dee3c7b90893d7d74952e82e4.","product_ids":["CSAFPID-1","CSAFPID-2"],"url":"https://github.com/elixir-grpc/grpc/commit/33b6a095dbc91c6dee3c7b90893d7d74952e82e4"}]}]}