Overview
About vulnerability
Summary
When responseType: ‘stream’ is used, Axios returns the response stream without enforcing maxContentLength. This bypasses configured response-size limits and allows unbounded downstream consumption.
Details
In lib/adapters/http.js:
- 786-789: for responseType === ‘stream’, Axios immediately settles with the stream.
- 797-810: maxContentLength enforcement exists only in the non-stream buffering branch.
So callers may set maxContentLength and still receive/read arbitrarily large streamed responses.
PoC
Environment:
- Axios main at commit f7a4ee2
- Node v24.2.0
Steps:
- Start an HTTP server that returns a 2 MiB response body.
- Call Axios with:
- adapter: ‘http’
- responseType: ‘stream’
- maxContentLength: 1024
- Read the returned stream fully.
Observed:
- Success; full 2097152 bytes readable.
Control check:
- Same endpoint with responseType: ’text’ and same maxContentLength: rejected with maxContentLength size of 1024 exceeded.
Impact
Type: DoS / unbounded response processing. Impacted: Node.js applications relying on maxContentLength as a safety boundary while using streamed Axios responses.
Details
- Affected product:
- axios , browser-sync , localtunnel , nguniversal
- Affected packages:
- axios @ 1.6.8 (+15 more)