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 firefoxUpgrade thunderbirdUpgrade firefox-x11 | Oct 11, 2026 | Sep 14, 2026 |
| Amazon_linux_2023 | — | Upgrade firefox-debugsourceUpgrade firefox-debuginfoUpgrade firefox | Sep 30, 2026 | Sep 1, 2026 |
| Debian | — | Upgrade firefox-esrUpgrade thunderbird | 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 the latest version of Mozilla FirefoxUpgrade to Mozilla Firefox ESR version 153.2 | Sep 1, 2026 | Sep 1, 2026 |
| Mozilla Thunderbird | — | Upgrade to the latest version of Mozilla ThunderbirdUpgrade to Mozilla Thunderbird version 153.2 | Sep 1, 2026 | Sep 1, 2026 |
| Redhat_linux | — | Upgrade firefoxUpgrade thunderbirdUpgrade firefox-x11Upgrade thunderbird-debugsourceUpgrade firefox-debuginfoUpgrade firefox-debugsourceNo solution existsUpgrade thunderbird-debuginfo | Sep 15, 2026 | Sep 1, 2026 |
| Rocky_linux | — | Upgrade firefoxUpgrade thunderbird-debuginfoUpgrade firefox-debugsourceUpgrade firefox-debuginfoUpgrade thunderbird-debugsourceUpgrade thunderbirdUpgrade firefox-x11 | Sep 28, 2026 | Sep 25, 2026 |
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