CVE-2026-42035
Axios: Header Injection via Prototype Pollution
Description
Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, a prototype pollution gadget exists in the Axios HTTP adapter (lib/adapters/http.js) that allows an attacker to inject arbitrary HTTP headers into outgoing requests. The vulnerability exploits duck-type checking of the data payload, where if Object.prototype is polluted with getHeaders, append, pipe, on, once, and Symbol.toStringTag, Axios misidentifies any plain object payload as a FormData instance and calls the attacker-controlled getHeaders() function, merging the returned headers into the outgoing request. The vulnerable code resides exclusively in lib/adapters/http.js. The prototype pollution source does not need to originate from Axios itself — any prototype pollution primitive in any dependency in the application's dependency tree is sufficient to trigger this gadget. This vulnerability is fixed in 1.15.1 and 0.31.1.
How to fix CVE-2026-42035
To remediate CVE-2026-42035, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 1.15.1 or later
Is CVE-2026-42035 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0
- >= 1.0.0, < 1.15.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |