CVE-2021-4129

Public Exploit

Description

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.

Category

9.8
CVSS
Severity: Critical
CVSS 3.1 •
EPSS 0.30%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Firefox
Affected: Mozilla Firefox ESR
Affected: Mozilla Thunderbird
Published at:
Updated at:

References

Link Tags
https://www.mozilla.org/security/advisories/mfsa2021-53/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2021-54/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2021-52/ vendor advisory
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1393362%2C1736046%2C1736751%2C1737009%2C1739372%2C1739421 vendor advisory issue tracking exploit

Frequently Asked Questions

What is the severity of CVE-2021-4129?
CVE-2021-4129 has been scored as a critical severity vulnerability.
How to fix CVE-2021-4129?
To fix CVE-2021-4129, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-4129 being actively exploited in the wild?
It is possible that CVE-2021-4129 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-4129?
CVE-2021-4129 affects Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird.
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