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Medium · 6.5 CVE-2025-50864 EUVD-2025-25313GHSA-f9qj-4c5x-cpcw

elysia-cors Origin Validation Error

Published Aug 20, 2025 · Updated Jul 5, 2026 · Assigned by mitre

Description

An Origin Validation Error in the elysia-cors library thru 1.3.0 allows attackers to bypass Cross-Origin Resource Sharing (CORS) restrictions. The library incorrectly validates the supplied origin by checking if it is a substring of any domain in the site's CORS policy, rather than performing an exact match. For example, a malicious origin like "notexample.com", "example.common.net" is whitelisted when the site's CORS policy specifies "example.com." This vulnerability enables unauthorized access to user data on sites using the elysia-cors library for CORS validation.

Affected packages

EcosystemPackageAffectedFixedRecord
npm @elysiajs/cors < 1.3.1 1.3.1 GHSA-f9qj-4c5x-cpcw

References