Mozilla: URL leakage when navigating while executing asynchronous function

The Mozilla Foundation Security Advisory describes this flaw as: Under certain circumstances, asynchronous functions could have caused a navigation to fail but expose the target URL...

UBUNTU-CVE-2021-43536

Under certain circumstances, asynchronous functions could have caused a navigation to fail but expose the target URL. This vulnerability affects Thunderbird 91.4.0, Firefox ESR 91.4.0, and Firefox 95...