Axios is a promise-based HTTP client for the browser and Node.js. From 1.16.1 until 1.20.0, the RFC 2397 regular expression allows slash characters on both sides of the media-type separator. An application passes an attacker-controlled malformed data URL containing many slash characters and no comma. the JavaScript regular-expression engine explores many separator placements before rejecting the URL. Synchronous excessive backtracking can block the Node.js event loop and cause denial of service. The affected identifiers are fromDataURI, DATA_URL_PATTERN, data:. This issue is fixed in version 1.20.0.
https://github.com/axios/axios/security/advisories/GHSA-c29m-xwm3-cm6r
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: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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