axios Improper Authentication Vulnerability - CVE-2026-42041

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1 the Axios library is vulnerable to a Prototype Pollution quotGadgetquot attack that allows any Object.prototype pollution to silently suppress all HTTP error responses (401 403 500 etc.) causing them to be treated as successful responses. This completely bypasses application-level authentication and error handling. The root cause is that validateStatus is the only config property using the mergeDirectKeys merge strategy which uses JavaScript39s in operator an operator that inherently traverses the prototype chain. When Object.prototype.validateStatus is polluted with () gt true all HTTP status codes are accepted as success. This vulnerability is fixed in 1.15.1 and 0.31.1.