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CVE-2026-84144

Internally found bugs fixed in Thunderbird 155 and Thunderbird ESR 153.2

Published: Sep 1, 2026Updated: Sep 3, 2026 Sources: CVE List NVDCWE-119
7.5HIGH
NVD MITRE
EPSS Score
0.2%
Top 84.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

Internally found bugs present in Thunderbird 154 and Thunderbird ESR 153.1. 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, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:RS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-119

Affected Products

Mozilla
oss-project·USaka mozilla corp.
FirefoxOn-premDesktop App
Consumer Software / browser
ThunderbirdOn-premDesktop App
Communications / email-server-client
and 2 more affected products View all →

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-84144?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054619%2C2054620%2C2054624%2C2054702%2C2054726%2C2054775%2C2055703%2C2058006%2C2058013%2C2058098%2C2058627%2C2058661%2C2059127%2C2059128%2C2059180%2C2059199%2C2059205%2C2061320%2C2061430%2C2061495%2C2061505%2C2061532%2C2061799
bugzilla.mozilla.org
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054625%2C2059002%2C2061775
bugzilla.mozilla.org
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054691%2C2058085%2C2059144%2C2059191%2C2059192%2C2061521%2C2062395%2C2062404
bugzilla.mozilla.org
and 4 more references View all →

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