CVE-2021-23995

Description

When Responsive Design Mode was enabled, it used references to objects that were previously freed. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

Category

8.8
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 1.02% Top 25%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Firefox ESR
Affected: Mozilla Thunderbird
Affected: Mozilla Firefox
Published at:
Updated at:

References

Link Tags
https://www.mozilla.org/security/advisories/mfsa2021-14/ release notes vendor advisory
https://www.mozilla.org/security/advisories/mfsa2021-16/ release notes vendor advisory
https://www.mozilla.org/security/advisories/mfsa2021-15/ release notes vendor advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1699835 vendor advisory issue tracking permissions required

Frequently Asked Questions

What is the severity of CVE-2021-23995?
CVE-2021-23995 has been scored as a high severity vulnerability.
How to fix CVE-2021-23995?
To fix CVE-2021-23995, 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-2021-23995 being actively exploited in the wild?
It is possible that CVE-2021-23995 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-23995?
CVE-2021-23995 affects Mozilla Firefox ESR, Mozilla Thunderbird, Mozilla Firefox.
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