CVE-2026-42040: low-severity vulnerability in axios
Axios: Null Byte Injection via Reverse-Encoding in AxiosURLSearchParams
Published · Updated
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8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 3.7epss 0.2%
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Affected products
axios · axiosRelated CVEs — axios
In the same product, most dangerous first.
CVE-2026-44492HIGHAxios: shouldBypassProxy does not recognize IPv4-mapped IPv6 addresses, allowing NO_PROXY bypass (incomplete fix for CVE-2025-62718)EPSS 12.3%CVE-2019-10742—CVE-2019-10742EPSS 6.1%CVE-2026-44496HIGHAxios: Regular Expression Denial of Service (ReDoS) via Cookie Name InjectionEPSS 5.4%CVE-2026-25639HIGHAxios affected by Denial of Service via __proto__ Key in mergeConfigEPSS 2.8%CVE-2026-40175MEDIUMAxios has Unrestricted Cloud Metadata Exfiltration via Header Injection ChainEPSS 2.0%CVE-2025-62718MEDIUMAxios has a NO_PROXY Hostname Normalization Bypass that Leads to SSRFEPSS 1.2%