High severity8.8NVD Advisory· Published Feb 26, 2021· Updated Jun 17, 2026
CVE-2021-23978
CVE-2021-23978
Description
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
44< 86+ 4 more
- (no CPE)range: < 86
- (no CPE)range: < 78.8
- (no CPE)range: <86
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*range: <86.0
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*range: <78.8
< 78.8+ 2 more
- (no CPE)range: < 78.8
- (no CPE)range: <78.8
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*range: <78.8
- osv-coords34 versionspkg:rpm/suse/MozillaThunderbird&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%20Crowbar%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2011%20SP4-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%209pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%20Crowbar%209pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP4-LTSSpkg: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%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Desktop%20Applications%2015%20SP2pkg:rpm/suse/MozillaFirefox&distro=HPE%20Helion%20OpenStack%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%207pkg: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%20SP2-BCLpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-BCLpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg: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%20Manager%20Server%204.0pkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Tumbleweedpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP3pkg:rpm/opensuse/firefox-esr&distro=openSUSE%20Tumbleweedpkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%208pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Leap%2015.2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Leap%2015.2
< 78.8.0-8.15.4+ 33 more
- (no CPE)range: < 78.8.0-8.15.4
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-78.120.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 78.8.0-8.32.2
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 91.1.1-1.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 128.5.1-1.1
- (no CPE)range: < 78.8.0-112.51.1
- (no CPE)range: < 92.0-1.2
- (no CPE)range: < 78.8.0-lp152.2.35.1
- (no CPE)range: < 78.8.0-3.133.1
- (no CPE)range: < 78.8.0-lp152.2.49.1
Patches
Vulnerability mechanics
References
8- bugzilla.mozilla.org/buglist.cginvdBroken LinkIssue TrackingVendor Advisory
- lists.debian.org/debian-lts-announce/2021/03/msg00000.htmlnvdMailing ListThird Party Advisory
- security.gentoo.org/glsa/202104-09nvdThird Party Advisory
- security.gentoo.org/glsa/202104-10nvdThird Party Advisory
- www.debian.org/security/2021/dsa-4866nvdThird Party Advisory
- www.mozilla.org/security/advisories/mfsa2021-07/nvdRelease NotesVendor Advisory
- www.mozilla.org/security/advisories/mfsa2021-08/nvdRelease NotesVendor Advisory
- www.mozilla.org/security/advisories/mfsa2021-09/nvdRelease NotesVendor Advisory
News mentions
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