Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. 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 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, 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 |
|---|---|---|---|---|
| Debian | — | Upgrade thunderbirdUpgrade firefox-esr | Sep 21, 2026 | Sep 1, 2026 |
| Mfsa2026 82 | — | Upgrade to Mozilla Firefox version 155.0Upgrade to the latest version of Mozilla Firefox | Sep 1, 2026 | Sep 1, 2026 |
| Mfsa2026 84 | — | Upgrade to the latest version of Mozilla FirefoxUpgrade to Mozilla Firefox ESR version 140.15 | Sep 1, 2026 | Sep 1, 2026 |
| Mfsa2026 85 | — | Upgrade to Mozilla Firefox ESR version 153.2Upgrade to the latest version of Mozilla Firefox | Sep 1, 2026 | Sep 1, 2026 |
| Mozilla Thunderbird | — | Upgrade to Mozilla Thunderbird version 153.2Upgrade to the latest version of Mozilla Thunderbird | Sep 1, 2026 | Sep 1, 2026 |
| Redhat_linux | — | Upgrade firefoxUpgrade thunderbirdUpgrade thunderbird-debugsourceUpgrade firefox-x11No solution existsUpgrade thunderbird-debuginfoUpgrade firefox-debugsourceUpgrade firefox-debuginfo | Sep 15, 2026 | Sep 1, 2026 |
| Rocky_linux | — | Upgrade firefox-debugsourceUpgrade firefox-debuginfoUpgrade thunderbird-debugsourceUpgrade firefoxUpgrade thunderbird-debuginfoUpgrade thunderbirdUpgrade firefox-x11 | Sep 28, 2026 | Sep 25, 2026 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub