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.
History

Fri, 24 Apr 2026 18:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Axios: Null Byte Injection via Reverse-Encoding in AxiosURLSearchParams
Weaknesses CWE-116
CWE-626
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-24T17:40:31.125Z

Reserved: 2026-04-23T16:05:01.709Z

Link: CVE-2026-42040

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-04-24T18:16:30.960

Modified: 2026-04-24T18:16:30.960

Link: CVE-2026-42040

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.