PT-2026-84528 · Mozilla · Thunderbird

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CVE-2026-84642

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Published

2026-09-01

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Updated

2026-09-05

CVSS v3.1

7.5

High

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Name of the Vulnerable Software and Affected Versions Thunderbird versions prior to 153.2 Thunderbird versions prior to 155
Description The mail.allowed attachment hostnames advanced configuration setting is used in a regular expression without proper escaping. This flaw allows certain unintended hostnames to match the expression, potentially enabling the serving of remote attachments from unauthorized hosts.
Recommendations Update Thunderbird to version 153.2 or later. Update Thunderbird to version 155 or later.

Fix

DoS

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Weakness Enumeration

Related Identifiers

CVE-2026-84642

Affected Products

Thunderbird