Axios is a promise-based HTTP client for the browser and Node.js. From 1.15.0 until 1.20.0, Axios shouldBypassProxy applies a quadratic trailing-dot regular expression to redirect hostnames. HTTP_PROXY or HTTPS_PROXY is configured, NO_PROXY or no_proxy is non-empty, redirects are followed, and a crafted redirect Location contains many dots followed by a non-dot character. Hostname.replace(/.+$/, '') backtracks quadratically while processing the crafted redirect hostname. Synchronous regular-expression processing can block the Node.js event loop and cause denial of service. This issue is fixed in version 1.20.0.
https://github.com/axios/axios/security/advisories/GHSA-mghh-pgcx-3jjj
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: 4.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P
Severity: Medium
Base Score: 8.2
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:H
Severity: High
Base Score: 8.2
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00402