CVSS 3.1
9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVE-2021-4129
Critical (9.8) in mozilla. EPSS 1.1% chance of exploitation in the next 30 days.
Mozilla developers and community members Julian Hector, Randell Jesup, Gabriele Svelto, Tyson Smith, Christian Holler, and Masayuki Nakano reported memory safety bugs present in Firefox 94. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 95, Firefox ESR < 91.4.0, and Thunderbird < 91.4.0.
Severity
- EPSS
- 1.1% chance of exploitation in the next 30 days; higher than 64% of CVEs (scores of 2026-10-31)
- CWE
- CWE-787
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mozilla:firefox
- mozilla:firefox_esr
- mozilla:thunderbird
References
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=1393362%2C1736046%2C1736751%2C1737009%2C1739372%2C1739421
- https://www.mozilla.org/security/advisories/mfsa2021-52/
- https://www.mozilla.org/security/advisories/mfsa2021-53/
- https://www.mozilla.org/security/advisories/mfsa2021-54/
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=1393362%2C1736046%2C1736751%2C1737009%2C1739372%2C1739421