If you’re building with JavaScript, there's a good chance you’ve used Axios for your HTTP requests. It’s everywhere — in backend services, browser apps, and powering thousands of packages. But a serious vulnerability, CVE-2026-40175, discovered in Axios versions prior to 1.15. and .3.1, opens the doors to remote code execution (RCE) and full cloud compromise if your app uses vulnerable dependencies.

Let’s break down what happened, how it can be exploited, and show you the code and references to truly understand the risk.

What is CVE-2026-40175?

CVE-2026-40175 is a critical security issue in Axios — specifically, it allows for a "Gadget" attack chain: If any dependency in your application is susceptible to Prototype Pollution, an attacker can escalate it using Axios to achieve RCE, or even access your cloud provider’s metadata (like AWS IMDSv2) and compromise your cloud account.

Official Advisory

- Axios Security Advisory for CVE-2026-40175 (Replace with official advisory when released.)

Impact: Possible Remote Code Execution or AWS Cloud Compromise

- Why Is This Dangerous?: With the right polluted object, Axios’s core processing can let attackers run arbitrary code.

What Is Prototype Pollution?

Prototype pollution means an attacker can inject properties into JavaScript’s fundamental object structure (Object.prototype). This is bad news, because many libraries, including Axios, copy or merge objects with user-supplied data.

Example

let obj = {};
let payload = JSON.parse('{"__proto__": {"evil": "run code"}}');
Object.assign(obj, payload);

console.log({}.evil); // prints "run code" - now every object shares 'evil'

If an attacker can get their payload merged into objects passed to Axios, they might control internal behaviors… and that’s where the danger starts.

Exploiting Axios

Axios’s request configuration and transfer logic merge options from user input. In vulnerable versions, certain polluted properties interact with Node.js or browser environment in unexpected ways — the so-called "gadget attack chain".

Suppose your app uses Axios like

const axios = require('axios');

app.post('/fetch', async (req, res) => {
  // User can POST JSON: { "url": "https://example.com"; }
  const { url } = req.body;
  const response = await axios.get(url);
  res.send(response.data);
});

Now, let’s assume some library in your app doesn’t protect against prototype pollution (like insecure lodash.merge versions). An attacker can POST:

{
  "url": "https://victim.com";,
  "__proto__": {
    "adapter": "my-malicious-function"
  }
}

If Axios in your app then uses an internal "adapter" setting (which controls how the HTTP request is sent in Node.js), and an attacker sets it via pollution, they could reach arbitrary code execution — adapters in Axios can be user-supplied functions.

Let’s say your app is vulnerable to prototype pollution, via a naive merge

const userInput = JSON.parse(request.body);
const options = {};
Object.assign(options, userInput);
await axios.request(options);

Attacker sends

{
  "__proto__": {
    "adapter": "(config) => { require('fs').writeFileSync('/tmp/pwned', 'owned'); return Promise.resolve({ data: 'OK', status: 200, statusText: 'OK', headers: {}, config }); }"
  }
}

If your code executes this, anyone could run code on your server!

Cloud Compromise: AWS IMDSv2 Bypass

Now, say you’re deploying on AWS and use temporary credentials. Axios, when processing the request, could be polluted so it makes an HTTP request to the AWS metadata API, retrieves fresh credentials, and these could be exfiltrated — in effect, an attacker gets “root” in your cloud.

The CVE details show how variants of this bug allow attackers to side-step security controls in AWS’ Instance Metadata Service (IMDSv2).

How to Fix the Problem

Update Immediately!
Upgrade Axios to 1.15. or .3.1 or newer.

- Axios Releases

Also, review your dependencies for *any* prototype pollution issues, especially widely used utilities like lodash, and never trust or merge raw user-provided objects.

Validate all incoming JSON.

- NEVER merge user input directly onto options/config objects.

Resources and References

- Axios Documentation
- Prototype Pollution in JavaScript
- AWS IMDSv2: Instance Metadata Service
- Axios Security Advisory (CVE-2026-40175) *(official CVE link when published)*

Final Thoughts

Hackers are always looking for creative ways to turn minor bugs into major exploits. CVE-2026-40175 is a dangerous reminder: small mistakes in handling objects and merging options can pierce all kinds of security boundaries — from code execution to full cloud compromise.

Patch now. Audit your dependencies. And always treat user input like a loaded gun.

*This article is exclusive to you. If you found it useful, share it to keep your friends — and your servers — safe.*

Timeline

Published on: 04/10/2026 19:23:52 UTC
Last modified on: 05/12/2026 13:17:34 UTC