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

Mon, 27 Apr 2026 20:15:00 +0000

Type Values Removed Values Added
First Time appeared Axios
Axios axios
CPEs cpe:2.3:a:axios:axios:*:*:*:*:*:node.js:*:*
Vendors & Products Axios
Axios axios

Mon, 27 Apr 2026 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


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

Updated: 2026-04-27T13:48:06.659Z

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

Link: CVE-2026-42040

cve-icon Vulnrichment

Updated: 2026-04-27T13:47:53.257Z

cve-icon NVD

Status : Analyzed

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

Modified: 2026-04-27T20:09:07.257

Link: CVE-2026-42040

cve-icon Redhat

No data.