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 thunderbirdUpgrade firefox | Oct 11, 2026 | Sep 14, 2026 |
| Amazon Linux Ami 2 | — | Upgrade firefox | Oct 19, 2026 | Oct 19, 2026 |
| Amazon_linux_2023 | — | Upgrade firefox-debugsourceUpgrade firefoxUpgrade firefox-debuginfo | Sep 30, 2026 | Sep 1, 2026 |
| Debian | — | Upgrade thunderbirdUpgrade firefox-esr | 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 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 Mozilla Thunderbird version 153.2Upgrade to the latest version of Mozilla Thunderbird | Sep 1, 2026 | Sep 1, 2026 |
| Oracle_linux | — | Upgrade thunderbirdUpgrade firefoxUpgrade firefox-x11 | Oct 22, 2026 | Sep 1, 2026 |
| Redhat_linux | — | Upgrade thunderbird-debugsourceUpgrade firefox-debugsourceNo solution existsUpgrade thunderbirdUpgrade thunderbird-debuginfoUpgrade firefox-x11Upgrade firefox-debuginfoUpgrade firefox | Sep 15, 2026 | Sep 1, 2026 |
| Rocky_linux | — | Upgrade firefox-x11Upgrade firefox-debuginfoUpgrade firefox-debugsourceUpgrade thunderbird-debuginfoUpgrade firefoxUpgrade thunderbird-debugsourceUpgrade thunderbird | Sep 28, 2026 | Sep 25, 2026 |
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