Executive brief
Axios is an HTTP client library widely used in Node.js and browser applications. A prototype pollution vulnerability allows an attacker who has already polluted JavaScript's Object.prototype (via a separate vulnerability in the app or a malicious dependency) to inject malicious request bodies, modify proxy settings, or alter URL serialization in axios requests. This could lead to data exposure, request interception, or manipulation of outgoing traffic.
Technical details
The vulnerability is a read-side prototype pollution gadget in axios that inherits polluted Object.prototype properties during request construction. The primary issue occurs in lib/core/Axios.js where bodyless method aliases (axios.get, axios.delete, axios.head, axios.options) read inherited data via (config || {}).data before config normalization, allowing attacker-controlled body data to be sent on requests that did not explicitly set a body. Secondary gadgets exist in low-level paths (lib/adapters/http.js and unsafe helpers) where config.proxy and config.paramsSerializer can inherit polluted values. Attack requires Object.prototype to be pre-polluted by another vulnerability. The issue is fixed in axios 1.18.0 and 0.33.0.
Affected products
- axios axios >=1.0.0 <=0.32.0 (primary); >= 0.33.0 and >= 1.18.0 patched
Timeline
- 2026-07-06: disclosed: Original advisory GHSA-mmx7-hfxf-jppx published
- 2026-07-06: patched: Fixed in axios 1.18.0 and 0.33.0