High severity8.8NVD Advisory· Published Feb 26, 2021· Updated Jun 17, 2026
CVE-2021-23960
CVE-2021-23960
Description
Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a potentially exploitable crash. 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/MozillaThunderbird&distro=openSUSE%20Leap%2015.2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%20Crowbar%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Enterprise%20Storage%205pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2011%20SP4-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%207pkg:rpm/opensuse/firefox-esr&distro=openSUSE%20Tumbleweedpkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%20Crowbar%209pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP3pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-BCLpkg: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%2012%20SP4-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg: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%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/suse/MozillaThunderbird&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%209pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP4pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-LTSSpkg:rpm/suse/MozillaThunderbird&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP1pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Manager%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%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Software%20Development%20Kit%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Manager%20Proxy%204.0pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Tumbleweedpkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%208pkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Leap%2015.1pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Leap%2015.1pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Leap%2015.2
< 78.7.0-lp152.2.29.1+ 38 more
- (no CPE)range: < 78.7.0-lp152.2.29.1
- (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: < 78.7.0-78.114.1
- (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: < 78.7.0-112.45.1
- (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: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-3.128.2
- (no CPE)range: < 78.7.0-8.9.1
- (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: < 78.7.0-8.26.2
- (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: < 78.7.0-3.128.2
- (no CPE)range: < 92.0-1.2
- (no CPE)range: < 91.1.1-1.1
- (no CPE)range: < 78.7.0-112.45.1
- (no CPE)range: < 78.7.0-lp151.2.69.1
- (no CPE)range: < 78.7.0-lp151.2.88.2
- (no CPE)range: < 78.7.0-lp152.2.43.1
Patches
Vulnerability mechanics
References
4- bugzilla.mozilla.org/show_bug.cginvdIssue TrackingPermissions RequiredVendor 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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