CVE-2026-27191

The record

Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. Versions 5.0.39 and below the redirect query parameter is appended to the base origin without validation, allowing attackers to steal access tokens via URL authority injection. This leads to full account takeover, as the attacker obtains the victim's access token and can impersonate them. The application constructs the final redirect URL by concatenating the base origin with the user-supplied redirect parameter. This is exploitable when the origins array is configured and origin values do not end with /. An attacker can supply @attacker.com as the redirect value results in https://target.com@attacker.com#access_token=..., where the browser interprets attacker.com as the host, leading to full account takeover. This issue has been fixed in version 5.0.40.

Affected packages

Related vulnerabilities

• GHSA-ppf9-4ffw-hh4p Feathers has an open redirect in OAuth callback enables account takeover Same vulnerability
• GHSA-wg9x-qfgw-pxhj Feathers has an OAuth Callback Account Takeover issue Also affects @feathersjs/authentication-oauth
• CVE-2026-29792 Feathersjs is a framework for creating web APIs and real-time applications with… Also affects @feathersjs/authentication-oauth
• CVE-2026-27193 Feathersjs is a framework for creating web APIs and real-time applications with… Also affects @feathersjs/authentication-oauth
• CVE-2026-27192 Feathersjs is a framework for creating web APIs and real-time applications with… Also affects @feathersjs/authentication-oauth
• GHSA-9m9c-vpv5-9g85 Feathers exposes internal headers via unencrypted session cookie Also affects @feathersjs/authentication-oauth
• GHSA-mp4x-c34x-wv3x Feathers has an origin validation bypass via prefix matching Also affects @feathersjs/authentication-oauth
• CVE-2026-87945 URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal SAML SSO… CWE-601