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.
In '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.
This issue affects grpc from 0.8.0 before 1.0.0.
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Affected Vendors & Products
References
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Mon, 15 Jun 2026 22:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. In '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. This issue affects grpc from 0.8.0 before 1.0.0. | |
| Title | Authorization bypass via path binding override in elixir-grpc/grpc HTTP transcoding | |
| First Time appeared |
Elixir-grpc
Elixir-grpc grpc |
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| Weaknesses | CWE-639 | |
| CPEs | cpe:2.3:a:elixir-grpc:grpc:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Elixir-grpc
Elixir-grpc grpc |
|
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: EEF
Published: 2026-06-15T21:55:28.702Z
Updated: 2026-06-15T21:55:28.702Z
Reserved: 2026-05-22T09:36:56.834Z
Link: CVE-2026-48599
No data.
Status : Received
Published: 2026-06-15T23:16:45.377
Modified: 2026-06-15T23:16:45.377
Link: CVE-2026-48599
No data.
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