vulnerability
MFSA2021-49 Firefox: Security Vulnerabilities fixed in Firefox ESR 91.3 (CVE-2021-38503)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 8 | (AV:N/AC:L/Au:N/C:P/I:P/A:P) | Nov 2, 2021 | Nov 3, 2021 | Aug 11, 2025 |
Severity
8
CVSS
(AV:N/AC:L/Au:N/C:P/I:P/A:P)
Published
Nov 2, 2021
Added
Nov 3, 2021
Modified
Aug 11, 2025
Description
The iframe sandbox rules were not correctly applied to XSLT stylesheets, allowing an iframe to bypass restrictions such as executing scripts or navigating the top-level frame. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.
Solution
mozilla-firefox-esr-upgrade-91_3
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