Name: CVE-2026-84142: Improper Restriction of Operations within the Bounds of a Memory Buffer
Creator: Rapid7
Published: 2026-09-01T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-84142, CWE-119, CWE-200, CVSS 9.8, EPSS 0.00561

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 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
Mfsa2026 82	—	Upgrade to Mozilla Firefox version 155.0Upgrade to the latest version of Mozilla Firefox	Sep 1, 2026	Sep 1, 2026
Mozilla Thunderbird	—	Upgrade to Mozilla Thunderbird version 155.0Upgrade to the latest version of Mozilla Thunderbird	Sep 1, 2026	Sep 1, 2026

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CVSS Details

Covered by Rapid7

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