CVE-2021-23987

HIGH

Firefox < 87.0 and Firefox ESR < 78.9 - Out-of-bounds Write

Title source: llm
STIX 2.1

Description

Mozilla developers and community members reported memory safety bugs present in Firefox 86 and Firefox ESR 78.8. 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 ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

References (4)

Core 4
Core References
Issue Tracking, Patch, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1513519%2C1683439%2C1690169%2C1690718

Scores

CVSS v3 8.8
EPSS 0.0025
EPSS Percentile 48.2%
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 < 87.0
mozilla/firefox_esr < 78.9
mozilla/thunderbird < 78.9
Published Mar 31, 2021
Tracked Since Feb 18, 2026