XPath Injection in Mozilla Firefox
CVE-2021-4140
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.
EPSS: 0.013 (67.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
Affected products
- Mozilla Firefox — versions unspecified
- Mozilla Firefox Esr — versions unspecified
- Mozilla Firefox_esr
- Mozilla Thunderbird — versions unspecified
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Exploit, Patch, Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-4140?
- CVE-2021-4140 is a critical-severity vulnerability in Mozilla Firefox, classified under XML Injection (Blind XPath Injection). CVSS score: 10.0/10. Published 2022-12-22.
- How severe is CVE-2021-4140?
- Critical severity. CVSS v3 base score is 10.0 out of 10.
- Is CVE-2021-4140 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.