The vulnerability in the implementation of the CORS (Cross-Origin Resource Sharing) mechanism in Firefox browsers, Firefox ESR, and the Thunderbird email client allows a perpetrator to circumvent security restrictions and gain unauthorized access to protected information.

The vulnerability of the CORS Cross-Origin Resource Sharing mechanism implementation in Firefox browsers, Firefox ESR, and the Thunderbird email client is related to the inclusion of functions from an unreliable controlled domain during the processing of the Access-Control-Allow-Credentials heade...