Axios: Null Byte Injection via Reverse-Encoding in AxiosURLSearchParams_CVE-2026-42040

3.7 / 10

LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

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.

Basic Information

ID CVE-2026-42040

Source GitHub_M

Published Apr 24, 2026 at 17:40

Affected Product

Vendor axios

Product axios

Version >= 1.0.0, < 1.15.1

Affected Versions axios axios >= 1.0.0, < 1.15.1
axios axios < 0.31.1

CWE Classification

CWE-116 CWE-626

References

github.com /axios/axios/security/advisories/GHSA-xhjh-pmcv-23jw

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    "published": "2026-04-24T17:40:31.125Z",
    "modified": "2026-04-24T17:40:31.125Z",
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