axios Permissive List of Allowed Inputs Vulnerability - CVE-2026-42042

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1 the Axios library39s XSRF token protection logic uses JavaScript truthy/falsy semantics instead of strict boolean comparison for the withXSRFToken config property. When this property is set to any truthy non-boolean value (via prototype pollution or misconfiguration) the same-origin check (isURLSameOrigin) is short-circuited causing XSRF tokens to be sent to all request targets including cross-origin servers controlled by an attacker. This vulnerability is fixed in 1.15.1 and 0.31.1.