# CVE-2026-42040

> Vulnerability · severity: **LOW** (CVSS 3.7).

## 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.

## Key facts

- **CVE ID:** CVE-2026-42040
- **Published:** 2026-04-24
- **CVSS severity:** LOW
- **CVSS base score:** 3.7
- **CWE codes:** CWE-116, CWE-626

## Affected products

- `axios:axios`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42040

## Citation

> AI Analytics. CVE-2026-42040. Retrieved 2026-08-24 from https://api.ai-analytics.org/cve/CVE-2026-42040. Derived from NIST NVD. Licensed CC0.

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