CVE-2021-23973
When trying to load a cross-origin resource in an audio/video context a decoding error may have resulted, and the content of that error may have revealed information about the resource. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8. Date published : 2021-02-25 https://www.debian.org/security/2021/dsa-4866