{"id":"CVE-2026-42040","aliases":["GHSA-xhjh-pmcv-23jw"],"url":"https://o3.security/vulnerability/CVE-2026-42040","summary":"Axios: Null Byte Injection via Reverse-Encoding in AxiosURLSearchParams","details":"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":"2026-04-24T17:40:31.125Z","modified":"2026-08-07T11:31:12.829977018Z","cvss":{"score":3.7,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"axios","fixedVersion":"1.15.1"},{"ecosystem":"npm","name":"axios","fixedVersion":"0.31.1"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42040.json"},{"type":"ADVISORY","url":"https://github.com/axios/axios/security/advisories/GHSA-xhjh-pmcv-23jw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42040"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:31:12.829977018Z"}}