A flaw was found in lodash. The fix for CVE-2021-23337 added validation for the variable option in _.template but did not apply the same validation to options.imports key names. Both paths flow into the same Function() constructor sink. Additionally, _.template uses assignInWith to merge imports, which enumerates inherited properties via for..in. If Object.prototype has been polluted by any other vector, the polluted keys are copied into the imports object and passed to Function().

A flaw was found in fast-uri. A remote attacker could exploit this vulnerability by crafting a malicious Uniform Resource Identifier (URI) that contains percent-encoded authority delimiters. The fast-uri library incorrectly decodes these delimiters during normalization and then re-emits them as raw separators, which can change the URI's intended authority. This issue allows applications that perform host allowlist checks, redirect validation, or outbound request routing to be steered to a different authority than specified, potentially bypassing security controls.

A flaw was found in webpack-dev-server. When a user configures a proxy with a broad context, such as '/', and enables WebSocket (ws: true) forwarding, the development server's own Hot Module Replacement (HMR) WebSocket can be intercepted. This interception leads to the leakage of the browser's cookies and Origin header to the proxy target, bypassing the server's Host/Origin validation. Additionally, it can corrupt the HMR socket, resulting in a denial of service for the HMR functionality.

A flaw was found in fast-uri. This vulnerability occurs because fast-uri fails to properly convert Unicode (Internationalized Domain Name - IDN) hostnames for HTTP-family URLs. This can lead to a situation where security policies, such as denylists or redirect validations, are bypassed when applications use fast-uri to enforce these policies before passing the URL to another parser. A remote attacker could exploit this to circumvent security controls and potentially access unauthorized resources or perform malicious redirects.