CVE-2021-4127
CriticalPublic PoC
Published: 22 December 2022
Published
22 December 2022
Modified
16 April 2025
KEV Added
—
Patch
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CVSS Score v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score
0.0070
72.4th percentile
Risk Priority
20
60% EPSS · 20% KEV · 20% CVSS
Summary
CVE-2021-4127 is a critical-severity an unspecified weakness vulnerability in Mozilla Firefox Esr. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 27.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-34001
Vulnerability details
An out of date graphics library (Angle) likely contained vulnerabilities that could potentially be exploited. This vulnerability affects Thunderbird < 78.9 and Firefox ESR < 78.9.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
mozilla
firefox esr
≤ 78.9.0
mozilla
thunderbird
≤ 78.9.0
Mitigating Controls
No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.