CVE-2026-101906Axios: ReDoS (O(N²)) in shouldBypassProxy host normalization, reachable via untrusted redirect Location

Description

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.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://github.com/axios/axios/security/advisories/GHSA-mghh-pgcx-3jjj
• https://github.com/axios/axios/pull/11141
• https://github.com/axios/axios/commit/d19040bda7a8be2f82c3c6e1a5bc03917daee39a
• https://github.com/axios/axios/releases/tag/v1.20.0