CVE-2026-42040 | THREATINT

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.

PUBLISHED Reserved 2026-04-23 | Published 2026-04-24 | Updated 2026-04-27 | Assigner GitHub_M

LOW: 3.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Problem types

CWE-116: Improper Encoding or Escaping of Output

CWE-626: Null Byte Interaction Error (Poison Null Byte)

Product status

>= 1.0.0, < 1.15.1

affected

< 0.31.1

affected

References

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

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

cve.org (CVE-2026-42040)

nvd.nist.gov (CVE-2026-42040)

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