CVE Catalog

CVE-2026-48599

HighCVSS 7.6
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.34%

27th percentile - higher than 27% of all known CVEs

Summary

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, so a path-bound field carries the attacker-supplied value rather than the router-extracted value. This issue affects grpc from 0.8.0 before 1.0.0.

Risk Assessment

Any handler that uses the path-bound field for authorization, multi-tenancy scoping, or ownership checks is silently bypassed, potentially leading to unauthorized access to other users' data. In multi-tenant applications this may result in leakage or modification of data belonging to other organizations.

Recommendation

Upgrade the grpc library to version 1.0.0 or later. Until then, verify that handlers do not rely solely on path-bound fields for authorization and add additional checks where necessary.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS