CVE-2021-4140criticalCWE-91

CVE-2021-4140: critical vulnerability in Mozilla Firefox

Published 22 Dec 2022 · Updated 16 Apr 2025

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28Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 9.8epss 1.4%

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Mozilla · Firefox Mozilla · Firefox ESR Mozilla · Thunderbird

Related CVEs — Mozilla Firefox

In the same product, most dangerous first.

CVE-2016-9079HIGHCVE-2016-9079EPSS 87.4%KEV CVE-2019-11708CRITICALCVE-2019-11708EPSS 55.9%KEV CVE-2019-17026HIGHCVE-2019-17026EPSS 46.3%KEV CVE-2019-11707HIGHCVE-2019-11707EPSS 38.0%KEV CVE-2024-9680CRITICALCVE-2024-9680EPSS 23.2%KEV CVE-2022-26485HIGHCVE-2022-26485EPSS 14.3%KEV

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1746720 https://www.mozilla.org/security/advisories/mfsa2022-01/https://www.mozilla.org/security/advisories/mfsa2022-02/https://www.mozilla.org/security/advisories/mfsa2022-03/