CVE-2021-23964: Mozilla Firefox

Mozilla developers reported memory safety bugs present in Firefox 84 and Firefox ESR 78.6.

No CVSS scoreEPSS 0.014 · 71st percentile

Published by the CVE Program (CNA: mozilla) at 26 Feb 2021, 15:29 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
Mozilla	Firefox	affected < 85
Mozilla	Thunderbird	affected < 78.7
Mozilla	Firefox ESR	affected < 78.7

Identifiers

CVE-2021-23964

CNA

mozilla

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

No source has published a CVSS score for this record yet.

CISA KEV Not listed.
EPSS 0.014, the 71st percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 26 Feb 2021. New records show when each source confirmed them.

Sources

References from the CNA

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.