Finished streaming calls keep reading a stalled request body indefinitely

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Affected versions of `connectrpc` start a background task to read the request body of every client-streaming and bidirectional-streaming call, before the interceptors or the handler run. A call can finish before it has consumed its request: the handler can return without reading all of its request stream, an interceptor can reject the call, or the request timeout can fire. The background task then keeps reading, with no time limit. If the client stops sending part-way through a message, or never sends the rest, the task, the partial message it has buffered (up to `max_message_size`, 4 MiB by default) and the HTTP/2 stream, or the HTTP/1.x connection, are held until the client finishes the stream or closes the connection.

Impact A client can use this to exhaust the memory, tasks and file descriptors of a server. With the default limits of the built-in `Server`, one HTTP/2 connection can hold 200 stalled streams, about 800 MiB at the default message size, and the server does not…

Published by the source

21 Sep 2026, 12:00 UTC

Last modified by the source

23 Sep 2026, 07:45 UTC

Source last checked

25 Oct 2026, 04:53 UTC

1. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

2. Revision 1 · created · 24 Oct 2026

   Published from osv record RUSTSEC-2026-0304

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# Patch Next advisory brief: GHSA-jx5x-3mcr-qp8r

Advisory: Finished streaming calls keep reading a stalled request body indefinitely
IDs: GHSA-jx5x-3mcr-qp8r
Record: https://patchnext.com/advisories/rustsec-2026-0304 (revision 2, source checked 25 Oct 2026, 04:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: connectrpc 0.9.1, 0.8.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io connectrpc: affected >= 0.2.0, < 0.8.2; >= 0.9.0, < 0.9.1; fixed in 0.8.2, 0.9.1

## Suggested inspection (read-only)
- crates.io connectrpc: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on connectrpc.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/RUSTSEC-2026-0304 (OSV record RUSTSEC-2026-0304 lists affected ranges: crates.io connectrpc >=0.2.0 =0.9.0 <0.9.1 (fixed))

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