CVE-2021-23978
HIGHFirefox < 86.0 and Firefox ESR < 78.8 - Out-of-bounds Write
Title source: llmDescription
Mozilla developers reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. 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 < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.
References (8)
Core 8
Core References
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-07/
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-09/
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-08/
Broken Link, Issue Tracking, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/buglist.cgi?bug_id=786797%2C1682928%2C1687391%2C1687597
Mailing List, Third Party Advisory mailing-list
x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2021/03/msg00000.html
Third Party Advisory vendor-advisory
x_refsource_debian
https://www.debian.org/security/2021/dsa-4866
Third Party Advisory vendor-advisory
x_refsource_gentoo
https://security.gentoo.org/glsa/202104-10
Third Party Advisory vendor-advisory
x_refsource_gentoo
https://security.gentoo.org/glsa/202104-09
Scores
CVSS v3
8.8
EPSS
0.0122
EPSS Percentile
79.3%
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 (5)
debian/debian_linux
9.0
debian/debian_linux
10.0
mozilla/firefox
< 86.0
mozilla/firefox_esr
< 78.8
mozilla/thunderbird
< 78.8
Published
Feb 26, 2021
Tracked Since
Feb 18, 2026