High severity8.8NVD Advisory· Published Feb 26, 2021· Updated Jun 17, 2026
CVE-2021-23964
CVE-2021-23964
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
47< 85+ 4 more
- (no CPE)range: < 85
- (no CPE)range: < 78.7
- (no CPE)range: <85
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*range: <85.0
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*range: <78.7
< 78.7+ 2 more
- (no CPE)range: < 78.7
- (no CPE)range: <78.7
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*range: <78.7
- osv-coords39 versionspkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Leap%2015.2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%20Crowbar%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%207pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP3pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP4pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Software%20Development%20Kit%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-BCLpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Enterprise%20Storage%205pkg:rpm/suse/MozillaThunderbird&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP1pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Desktop%20Applications%2015%20SP1pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Manager%20Proxy%204.0pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Desktop%20Applications%2015%20SP2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%20Crowbar%209pkg:rpm/suse/MozillaThunderbird&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2011%20SP4-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP4-LTSSpkg:rpm/opensuse/firefox-esr&distro=openSUSE%20Tumbleweedpkg:rpm/suse/MozillaFirefox&distro=HPE%20Helion%20OpenStack%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%209pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-BCLpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Tumbleweedpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Manager%20Server%204.0pkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Leap%2015.1pkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Leap%2015.1pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Tumbleweed
< 78.7.0-lp152.2.43.1+ 38 more
- (no CPE)range: < 78.7.0-lp152.2.43.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-3.119.1
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-8.26.2
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-8.9.1
- (no CPE)range: < 78.7.0-78.114.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 128.5.1-1.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 91.1.1-1.1
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-lp151.2.69.1
- (no CPE)range: < 78.7.0-lp152.2.29.1
- (no CPE)range: < 78.7.0-lp151.2.88.2
- (no CPE)range: < 92.0-1.2
Patches
Vulnerability mechanics
References
4- bugzilla.mozilla.org/buglist.cginvdBroken LinkIssue TrackingVendor Advisory
- www.mozilla.org/security/advisories/mfsa2021-03/nvdRelease NotesVendor Advisory
- www.mozilla.org/security/advisories/mfsa2021-04/nvdRelease NotesVendor Advisory
- www.mozilla.org/security/advisories/mfsa2021-05/nvdRelease NotesVendor Advisory
News mentions
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