GHSA-vf2m-468p-8v99
Axios: HTTP adapter streamed responses bypass maxContentLength
Details
### 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:
1. Start an HTTP server that returns a 2 MiB response body. 2. Call Axios with: - adapter: 'http' - responseType: 'stream' - maxContentLength: 1024 3. 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.
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