Axios is a promise-based HTTP client for the browser and Node.js. From 1.0.0 until 1.20.0, the dispatchRequest function normalizes inherited Object.prototype.headers from a replacement request configuration. A separate same-process prototype-pollution flaw sets Object.prototype.headers, and trusted request interceptors return a new ordinary configuration without an own headers property. After the interceptor chain, dispatchRequest resolves the inherited headers during normalization. Downstream request processing can observe attacker-controlled headers, including authorization-related values. This issue is fixed in version 1.20.0.
https://github.com/axios/axios/security/advisories/GHSA-j8rh-479h-cp32
https://github.com/axios/axios/releases/tag/v1.20.0
https://github.com/axios/axios/pull/11141
https://github.com/axios/axios/commit/d19040bda7a8be2f82c3c6e1a5bc03917daee39a
Published: 2026-09-28
Updated: 2026-09-28
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 9.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Severity: Critical
Base Score: 6.9
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:H/SA:N
Severity: Medium