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.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade thunderbirdUpgrade firefoxUpgrade firefox-x11 | Oct 11, 2026 | Sep 14, 2026 |
| Amazon Linux Ami 2 | — | Upgrade firefox | Oct 19, 2026 | Oct 19, 2026 |
| Amazon_linux_2023 | — | Upgrade firefoxUpgrade firefox-debuginfoUpgrade firefox-debugsource | Sep 30, 2026 | Sep 1, 2026 |
| 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 Mozilla Firefox ESR version 140.15Upgrade to the latest version of Mozilla Firefox | 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 |
| Oracle_linux | — | Upgrade firefoxUpgrade thunderbirdUpgrade firefox-x11 | Oct 22, 2026 | Sep 1, 2026 |
| Redhat_linux | — | Upgrade thunderbirdUpgrade firefoxUpgrade thunderbird-debugsourceUpgrade firefox-debuginfoUpgrade firefox-debugsourceUpgrade firefox-x11No solution existsUpgrade thunderbird-debuginfo | Sep 15, 2026 | Sep 1, 2026 |
| Rocky_linux | — | Upgrade thunderbird-debugsourceUpgrade firefoxUpgrade firefox-debuginfoUpgrade thunderbird-debuginfoUpgrade firefox-debugsourceUpgrade firefox-x11Upgrade thunderbird | Sep 28, 2026 | Sep 25, 2026 |
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