CVE-2021-23960

Description

Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a potentially exploitable crash. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.

8.8

CVSS

Severity: High

CVSS 3.1 •

CVSS 2.0 •

EPSS 0.42%

Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org

Affected: Mozilla Firefox

Affected: Mozilla Thunderbird

Affected: Mozilla Firefox ESR

References

Link	Tags
https://www.mozilla.org/security/advisories/mfsa2021-03/	release notes vendor advisory
https://www.mozilla.org/security/advisories/mfsa2021-04/	release notes vendor advisory
https://www.mozilla.org/security/advisories/mfsa2021-05/	release notes vendor advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1675755	issue tracking permissions required vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-23960?: CVE-2021-23960 has been scored as a high severity vulnerability.
How to fix CVE-2021-23960?: To fix CVE-2021-23960, 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-2021-23960 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2021-23960 is being actively exploited. 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-2021-23960?: CVE-2021-23960 affects Mozilla Firefox, Mozilla Thunderbird, Mozilla Firefox ESR.

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