CVE-2021-23964

HIGH

Firefox < 85.0 and Firefox ESR < 78.7 - Out-of-bounds Write

Title source: llm

Description

Mozilla developers reported memory safety bugs present in Firefox 84 and Firefox ESR 78.6. 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 < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.

References (4)

Core 4

Core References

Release Notes, Vendor Advisory x_refsource_misc

https://www.mozilla.org/security/advisories/mfsa2021-03/

Release Notes, Vendor Advisory x_refsource_misc

https://www.mozilla.org/security/advisories/mfsa2021-04/

Release Notes, Vendor Advisory x_refsource_misc

https://www.mozilla.org/security/advisories/mfsa2021-05/

Broken Link, Issue Tracking, Vendor Advisory x_refsource_misc

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1662507%2C1666285%2C1673526%2C1674278%2C1674835%2C1675097%2C1675844%2C1675868%2C1677590%2C1677888%2C1680410%2C1681268%2C1682068%2C1682938%2C1683736%2C1685260%2C1685925

Scores

CVSS v3 8.8

EPSS 0.0038

EPSS Percentile 59.3%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Details

CWE

CWE-787

Status published

Products (3)

mozilla/firefox < 85.0

mozilla/firefox_esr < 78.7

mozilla/thunderbird < 78.7

Published Feb 26, 2021

Tracked Since Feb 18, 2026