Mozilla developers reported memory safety bugs present in Firefox 83 and Firefox ESR 78.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade librewolfUpgrade firefox-esrUpgrade mozjs78Upgrade firefoxUpgrade thunderbird | Jan 19, 2021 | Jan 7, 2021 |
| Amazon Linux Ami 2 | — | Upgrade thunderbirdUpgrade thunderbird-debuginfo | Jan 8, 2021 | Jan 8, 2021 |
| Arch Linux | — | Upgrade to the latest version of Arch Linux | Jul 11, 2025 | Jan 7, 2021 |
| Centos_linux | — | Upgrade thunderbirdUpgrade thunderbird-debugsourceUpgrade firefoxUpgrade firefox-debuginfoUpgrade thunderbird-debuginfoUpgrade firefox-debugsource | Dec 21, 2020 | Dec 16, 2020 |
| Debian | — | Upgrade firefox-esrUpgrade thunderbird | Dec 18, 2020 | Dec 18, 2020 |
| Gentoo Linux | — | Upgrade mail-client/thunderbird.Upgrade www-client/firefox-bin.Upgrade www-client/firefox.Upgrade mail-client/thunderbird-bin. | Dec 29, 2020 | Dec 23, 2020 |
| Mfsa2020 54 | — | Upgrade to the latest version of Mozilla FirefoxUpgrade to Mozilla Firefox version 84.0 | Dec 16, 2020 | Dec 15, 2020 |
| Mfsa2020 55 | — | Upgrade to the latest version of Mozilla FirefoxUpgrade to Mozilla Firefox ESR version 78.6 | Dec 16, 2020 | Dec 15, 2020 |
| Mozilla Thunderbird | — | Upgrade to the latest version of Mozilla ThunderbirdUpgrade to Mozilla Thunderbird version 78.6 | Dec 16, 2020 | Dec 15, 2020 |
| Oracle Solaris | — | Upgrade library/libmozjs-78 to version 78.11.0-11.4.39.0.1.107.0 on Solaris 11.4Upgrade mail/thunderbird to version 78.6.0-11.4.30.0.1.88.0 on Solaris 11.4 | Feb 17, 2021 | Jan 7, 2021 |
| Oracle_linux | — | Upgrade thunderbirdUpgrade firefox | Dec 17, 2020 | Dec 15, 2020 |
| Redhat_linux | — | Upgrade firefox-debuginfoUpgrade thunderbird-debugsourceUpgrade firefox-debugsourceNo solution existsUpgrade thunderbird-debuginfoUpgrade thunderbirdUpgrade firefox | Dec 21, 2020 | Dec 16, 2020 |
| Suse | — | Upgrade MozillaFirefox-develUpgrade MozillaThunderbirdUpgrade MozillaThunderbird-translations-otherUpgrade mozillafirefox-buildsymbolsUpgrade MozillaFirefox-translations-otherUpgrade MozillaThunderbird-translations-commonUpgrade MozillaFirefox-translations-commonUpgrade MozillaFirefoxUpgrade mozillafirefox-branding-upstream | Dec 22, 2020 | Dec 15, 2020 |
| Ubuntu | — | Upgrade firefoxUpgrade thunderbird | Dec 16, 2020 | Dec 15, 2020 |
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