CVE-2026-42040
Axios: Null Byte Injection via Reverse-Encoding in AxiosURLSearchParams
CVSS Score
3.7
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-116 CWE-626 |
| Vendor | axios |
| Product | axios |
| Published | Apr 24, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None
Affected Versions
axios / axios
>= 1.0.0, < 1.15.1 < 0.31.1