Critical severity9.8NVD Advisory· Published Sep 1, 2026· Updated Sep 3, 2026
CVE-2026-84142
CVE-2026-84142
Description
Internally found bugs present in Thunderbird 154. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155 and Thunderbird 155.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
6- Range: <155
- osv-coords5 versionspkg:apk/chainguard/firefoxpkg:apk/wolfi/firefox-docker-selenium-compatpkg:apk/wolfi/firefoxpkg:apk/chainguard/firefox-docker-selenium-compatpkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Tumbleweed
< 155.0.1-r0+ 4 more
- (no CPE)range: < 155.0.1-r0
- (no CPE)range: < 155.0.1-r0
- (no CPE)range: < 155.0.1-r0
- (no CPE)range: < 155.0.1-r0
- (no CPE)range: < 155.0-1.1
Patches
Vulnerability mechanics
References
4- www.mozilla.org/security/advisories/mfsa2026-82/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-86/nvdVendor Advisory
- bugzilla.mozilla.org/buglist.cginvdIssue Tracking
- bugzilla.mozilla.org/buglist.cginvdIssue Tracking
News mentions
2- Mozilla Thunderbird: 16 Vulnerabilities Including Critical Sandbox Escapes Disclosed TogetherVypr Intelligence · Sep 1, 2026
- Mozilla Firefox & Thunderbird: 25 Vulnerabilities Including Critical Sandbox Escapes Disclosed TogetherVypr Intelligence · Sep 1, 2026