Improper Encoding or Escaping of Output Affecting axios package, versions <0.31.1>=1.0.0 <1.15.1
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-JS-AXIOS-16298055
- published26 Apr 2026
- disclosed24 Apr 2026
- creditAugust829
Introduced: 24 Apr 2026
NewCVE-2026-42040 (opens in a new tab)How to fix?
Upgrade axios to version 0.31.1, 1.15.1 or higher.
Overview
axios is a promise-based HTTP client for the browser and Node.js.
Affected versions of this package are vulnerable to Improper Encoding or Escaping of Output through the encode function in AxiosURLSearchParams. An attacker can smuggle a NUL byte into serialized query strings by supplying crafted parameter values, causing downstream parsers or backend components to misinterpret the request and potentially truncate or alter parameter handling.
Notes: Standard axios request flow (buildURL) uses its own encode function, which does NOT have this bug. Only triggered via direct AxiosURLSearchParams.toString() without an encoder, or via custom paramsSerializer delegation