It was possible to construct specific XSLT markup that would be able to bypass an iframe sandbox. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
https://www.mozilla.org/security/advisories/mfsa2022-03/
https://www.mozilla.org/security/advisories/mfsa2022-02/
https://www.mozilla.org/security/advisories/mfsa2022-01/
Source: Mitre, NVD
Published: 2022-12-22
Base Score: 10
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
Severity: Critical
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H