CVE-2026-101909

A vulnerability in the axios library allows sending requests to absolute URLs instead of relative ones, potentially leading to SSRF attacks and credential leakage. Even with baseURL set, axios ignores it and sends the request to the specified absolute URL.

Axios versions 0.28.0 and later contain uncontrolled recursion in formDataToJSON, the helper behind the public axios.formToJSON() / named formToJSON API and the default request transform used when FormData is sent with an application/json content type.

Axios is vulnerable to read-side prototype-pollution gadgets when Object.prototype has already been polluted by another vulnerability or dependency. The most broadly reachable issue is in the bodyless method aliases: axios.get(), axios.delete(), axios.head(), and axios.options().

Axios can consume inherited properties from nested request option objects when the JavaScript process already has a polluted Object.prototype. The top-level merged config is protected with a null prototype, but nested plain objects such as auth and paramsSerializer are cloned into objects with a prototype.

An issue in Axios 1.5.1 inadvertently reveals the confidential XSRF-TOKEN stored in cookies by including it in the HTTP header X-XSRF-TOKEN for every request made to any host, allowing attackers to view sensitive information.

Axios versions starting with 0.28.0 contain uncontrolled recursion in formDataToJSON, which is exposed as axios.formToJSON() and used internally when axios serialises FormData with Content-Type: application/json. If an application passes attacker-controlled FormData field names, it can lead to stack exhaustion.

A vulnerability in Axios prior to versions 1.15.0 and 0.31.0 incorrectly handles hostname normalization when checking NO_PROXY rules. Requests to loopback addresses like localhost. (with a trailing dot) or [::1] (IPv6 literal) skip NO_PROXY matching and go through the configured proxy.

In Axios from version 1.7.0 to 1.20.0, the fetch adapter constructs a Request with sanitized resolvedOptions but then calls fetch with the original fetchOptions. A separate same-process prototype-pollution flaw populates Object.prototype.headers so fetchOptions.headers resolves through inheritance. The inherited fetchOptions.headers value overrides the sanitized Request headers through the second argument to fetch after Request construction. Attacker-controlled request headers can alter authorization, caching, metadata-service access, or application-specific behavior.

Axios from 1.17.0 until 1.20.0 in the fetch adapter bypasses the maxRedirects: 0 redirect policy. An Axios request uses the fetch adapter with maxRedirects set to zero and receives a redirect response, but the underlying fetch implementation follows the redirect instead of returning the redirect response unchanged. The redirected request can access internal responses or reach state-changing internal endpoints despite redirects being disabled.

Axios from 1.15.0 until 1.20.0 in shouldBypassProxy applies a quadratic trailing-dot regular expression to redirect hostnames. When HTTP_PROXY or HTTPS_PROXY is configured, NO_PROXY or no_proxy is non-empty, redirects are followed, and a crafted redirect Location contains many dots followed by a non-dot character, the regular expression can backtrack quadratically, blocking the Node.js event loop and causing denial of service.