CVE-2026-42040: Axios

Low severity, CVSS 3.7. EPSS: 0.3% chance of exploitation in the next 30 days.

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, the encode() function in lib/helpers/AxiosURLSearchParams.js contains a character mapping (charMap) at line 21 that reverses the safe percent-encoding of null bytes. After encodeURIComponent('\x00') correctly produces the safe sequence %00, the charMap entry '%00': '\x00' converts it back to a raw null byte. Primary impact is limited because the standard axios request flow is not affected. This vulnerability is fixed in 1.15.1 and 0.31.1.

Affected products

• Axios Axios: before 0.31.1 (fixed in 0.31.1); from 1.0.0, before 1.15.1 (fixed in 1.15.1)

Published 2026-04-24. Last modified 2026-06-17.