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CVE-2026-84142

security@mozilla.org
CRITICAL
CVSS Score:9.8/10
Modified
Published: 9/1/2026
Modified: 9/3/2026
2 Affected Products
Risk Assessment
100%
Exploitability
100%
Impact
Overall Risk: 98%
Vulnerability 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.

CVSS v3.1 Score
9.8
CRITICAL
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.9
Exploitability
5.9
Impact
Attack Vector Analysis
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH

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