CVE-2026-123635
Received
Received - Intake
Resource Exhaustion via Flow Control in Elixir gRPC Server
Vulnerability report for CVE-2026-123635, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-11-13
Last updated on: 2026-11-13
Assigner: EEF
Description
Description
Missing Release of Resource after Effective Lifetime vulnerability in elixir-grpc grpc_server allows a client to stall all later calls on a shared HTTP/2 connection via calls that the server refuses while their DATA frames are in flight.
The stream handler grpc_stream_h (grpc_server/src/grpc_stream_h.erl) requests flow from Cowboy only for request data that has arrived. When the server refuses a call early, for example because the body exceeds max_body_size or the method is not implemented, Cowboy drops the DATA frames still in flight for that stream. Their bytes are not returned to the connection flow-control window. After enough refused calls the window is empty. No call on that connection can then send a request body, and each call waits until its deadline. Other connections are not affected.
This issue affects grpc_server: from 1.0.0 before 1.1.0.
CVSS Scores
EPSS Scores
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| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| elixir-grpc | grpc_server | From 1.0.0 (inc) to 1.1.0 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-772 | The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed. |
