CVE-2021-38505

The Mozilla Foundation Security Advisory describes this flaw as:

Microsoft introduced a new feature in Windows 10 known as Cloud Clipboard which, if enabled, will record data copied to the clipboard to the cloud, and make it available on other computers in certain scenarios. Applications that wish to prevent copied data from being recorded in Cloud History must use specific clipboard formats; and Firefox before versions 94 and ESR 91.3 did not implement them. This could have caused sensitive data to be recorded to a user's Microsoft account. This bug only affects Firefox for Windows 10+ with Cloud Clipboard enabled. Other operating systems are unaffected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.