VULNERABILITY INTELLIGENCE
CVE-2021-38503
CVSS score10 CRITICAL
EPSS probability4.12%
CISA KEVNot currently listed
Published2021-12-08
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
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.
Weakness classification
- nvd@nist.gov: CWE-863
Primary references
- security@mozilla.org — Issue Tracking, Permissions Required, Vendor Advisory
- security@mozilla.org — Mailing List, Third Party Advisory
- security@mozilla.org — Mailing List, Third Party Advisory
- security@mozilla.org — Third Party Advisory
- security@mozilla.org — Third Party Advisory
- security@mozilla.org — Third Party Advisory
- security@mozilla.org — Third Party Advisory
- security@mozilla.org — Vendor Advisory
- security@mozilla.org — Vendor Advisory
- security@mozilla.org — Vendor Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Issue Tracking, Permissions Required, Vendor Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Mailing List, Third Party Advisory