Vulnerability · Published Jun 15, 2026 · Assigned by EEF
CVE-2026-48599Authorization bypass via path binding override in elixir-grpc/grpc HTTP transcoding
High 7.6
In plain English
A high-severity authorization bypass via user-controlled key in grpc from elixir-grpc. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| elixir-grpc | grpc | 0.8.0 – before 1.0.0 |
| elixir-grpc | grpc | 8aaf3d3a8c4c7b08ac65e9c6f254e0d24da1d048 – before 33b6a095dbc91c6dee3c7b90893d7d74952e82e4 |
Weakness: CWE-639 · Vector: 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