If an attacker could control the contents of an iframe sandboxed with <code>allow-popups</code> but not <code>allow-scripts</code>, they were able to craft a link that, when clicked, would lead to JavaScript execution in violation of the sandbox. This vulnerability affects Firefox < 98, Firefox ESR < 91.7, and Thunderbird < 91.7.
https://www.mozilla.org/security/advisories/mfsa2022-12/
https://www.mozilla.org/security/advisories/mfsa2022-11/