GRPC.Server.Adapters.Cowboy.read_stream/1 (grpc_server/lib/grpc/server/adapters/cowboy.ex, and the Cowboy adapter in grpc before the package split) asks for more data whenever the buffer does not hold a complete message. Once the request body has ended, every further read returns an empty chunk, so the buffer never changes and the function retries without end. A single 5-byte length prefix sent with END_STREAM keeps one scheduler busy for as long as the connection stays open, and repeated requests exhaust all schedulers.
This issue affects grpc_server: from 1.0.0 before 1.1.0; grpc: from 0.3.1 before 1.0.0.
Analysis and contextual insights are available on OpenCVE Cloud.
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Fri, 13 Nov 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in elixir-grpc grpc_server and grpc allows unauthenticated attackers to occupy a BEAM scheduler indefinitely via a client-streaming or bidirectional-streaming request whose body ends inside a gRPC message. GRPC.Server.Adapters.Cowboy.read_stream/1 (grpc_server/lib/grpc/server/adapters/cowboy.ex, and the Cowboy adapter in grpc before the package split) asks for more data whenever the buffer does not hold a complete message. Once the request body has ended, every further read returns an empty chunk, so the buffer never changes and the function retries without end. A single 5-byte length prefix sent with END_STREAM keeps one scheduler busy for as long as the connection stays open, and repeated requests exhaust all schedulers. This issue affects grpc_server: from 1.0.0 before 1.1.0; grpc: from 0.3.1 before 1.0.0. | |
| Title | CPU exhaustion via a truncated gRPC message on streaming RPCs in elixir-grpc grpc_server | |
| First Time appeared |
Elixir-grpc
Elixir-grpc grpc Elixir-grpc grpc Server |
|
| Weaknesses | CWE-400 CWE-835 |
|
| CPEs | cpe:2.3:a:elixir-grpc:grpc:*:*:*:*:*:*:*:* cpe:2.3:a:elixir-grpc:grpc_server:*:*:*:*:*:*:*:* |
|
| Vendors & Products |
Elixir-grpc
Elixir-grpc grpc Elixir-grpc grpc Server |
|
| References |
|
|
| Metrics |
cvssV4_0
|
Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-11-13T19:32:40.114Z
Reserved: 2026-11-13T11:19:13.834Z
Link: CVE-2026-121809
No data.
Status : Received
Published: 2026-11-13T17:17:19.310
Modified: 2026-11-13T17:17:19.310
Link: CVE-2026-121809
No data.
OpenCVE Enrichment
Updated: 2026-11-13T19:30:21Z