VDB
KO
MEDIUM 5.3

GHSA-5c9x-8gcm-mpgx

Axios' HTTP adapter-streamed uploads bypass maxBodyLength when maxRedirects: 0

Details

### Summary

For stream request bodies, maxBodyLength is bypassed when maxRedirects is set to 0 (native http/https transport path). Oversized streamed uploads are sent fully even when the caller sets strict body limits.

### Details

Relevant flow in lib/adapters/http.js: - 556-564: maxBodyLength check applies only to buffered/non-stream data. - 681-682: maxRedirects === 0 selects native http/https transport. - 694-699: options.maxBodyLength is set, but native transport does not enforce it. - 925-945: stream is piped directly to socket (data.pipe(req)) with no Axios byte counting.

This creates a path-specific bypass for streamed uploads.

### PoC

Environment:

- Axios main at commit f7a4ee2 - Node v24.2.0

Steps: 1. Start an HTTP server that counts uploaded bytes and returns {received}. 2. Send a 2 MiB Readable stream with: - adapter: 'http' - maxBodyLength: 1024 - maxRedirects: 0

Observed: - Request succeeds; server reports received: 2097152.

Control checks: - Same stream with default/nonzero redirects: rejected with ERR_FR_MAX_BODY_LENGTH_EXCEEDED. - Buffered body with maxRedirects: 0: rejected with ERR_BAD_REQUEST.

### Impact Type: DoS / uncontrolled upstream upload / resource exhaustion. Impacted: Node.js services using streamed request bodies with maxBodyLength expecting hard enforcement, especially when following Axios guidance to use maxRedirects: 0 for streams.

Are you affected?

Enter the version of the package you're using.

Affected packages

npm / axios
Introduced in: 1.0.0 Fixed in: 1.15.1
Fix npm install axios@1.15.1
npm / axios
Introduced in: 0 Fixed in: 0.31.1
Fix npm install axios@0.31.1

References