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 115.40, 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 firefox-x11Upgrade firefoxUpgrade thunderbird | Oct 11, 2026 | Sep 14, 2026 |
| Amazon_linux_2023 | — | Upgrade firefox-debuginfoUpgrade firefoxUpgrade firefox-debugsource | Sep 30, 2026 | Sep 1, 2026 |
| Debian | — | Upgrade firefox-esrUpgrade thunderbird | Sep 21, 2026 | Sep 1, 2026 |
| Mfsa2026 82 | — | Upgrade to the latest version of Mozilla FirefoxUpgrade to Mozilla Firefox version 155.0 | Sep 1, 2026 | Sep 1, 2026 |
| Mfsa2026 83 | — | Upgrade to Mozilla Firefox ESR version 115.40Upgrade 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 the latest version of Mozilla ThunderbirdUpgrade to Mozilla Thunderbird version 153.2 | Sep 1, 2026 | Sep 1, 2026 |
| Redhat_linux | — | Upgrade thunderbird-debugsourceUpgrade firefoxUpgrade thunderbird-debuginfoUpgrade thunderbirdUpgrade firefox-debugsourceNo solution existsUpgrade firefox-x11Upgrade firefox-debuginfo | Sep 15, 2026 | Sep 1, 2026 |
| Rocky_linux | — | Upgrade firefox-debugsourceUpgrade firefox-debuginfoUpgrade firefox-x11Upgrade thunderbird-debuginfoUpgrade firefoxUpgrade thunderbirdUpgrade thunderbird-debugsource | Sep 28, 2026 | Sep 25, 2026 |
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