Name: CVE-2026-84637: Unrestricted Upload of File with Dangerous Type
Creator: Rapid7
Published: 2026-09-01T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-84637, CWE-434, CVSS 9.8, EPSS 0.00626

Malicious calendar invitations could use file URI attachments to launch local or network-hosted executables on Windows, bypassing Thunderbird's normal executable attachment protections. With the new invitation display enabled, the attachment could also appear under a misleading filename. This vulnerability was fixed in Thunderbird 154 and Thunderbird 153.2.

CVSS Details

CVSS 3.1 Base Score: 9.8
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Mozilla Thunderbird	—	Upgrade to Mozilla Thunderbird version 153.2Upgrade to the latest version of Mozilla Thunderbird	Sep 1, 2026	Sep 1, 2026
Redhat_linux	—	—	Sep 3, 2026	Sep 1, 2026

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CVSS Details

Covered by Rapid7

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