Executive brief
Axios, a popular library for making web requests, contains a flaw in how it handles proxy settings in Node.js environments. If an attacker has already compromised the application's environment through a separate "prototype pollution" vulnerability, they can force Axios to send sensitive data—including login credentials and request bodies—through a server they control. This could lead to the theft of customer data or authentication tokens used by the application.
Technical details
Axios attempts to harden its configuration against prototype pollution by using null-prototype objects. However, a bypass exists when request interceptors use common immutable patterns (like spread operators or Object.assign) to return a modified config, which re-materializes the config as a standard object. In Node.js environments using the HTTP adapter, the 'config.proxy' property is subsequently read through the prototype chain. If 'Object.prototype.proxy' has been polluted, Axios will route requests through the malicious proxy. This allows for the disclosure of Authorization headers, Basic auth credentials, and request bodies over plaintext HTTP. Patches are available in versions 0.33.0 and 1.18.0.
Affected products
- axios axios >= 0.31.1, < 0.33.0; >= 1.15.2, < 1.18.0
Timeline
- 2026-07-06: disclosed
- 2026-07-20: advisory: GHSA-gcfj-64vw-6mp9 published
- 2026-07-20: patched
References
- https://api.github.com/users/thesmartshadow
- https://github.com/thesmartshadow
- https://api.github.com/users/thesmartshadow/gists%7B/gist_id%7D
- https://api.github.com/users/thesmartshadow/repos
- https://avatars.githubusercontent.com/u/33183887?v=4
- https://api.github.com/users/thesmartshadow/events%7B/privacy%7D