The Quarterly Threat Landscape Report is out. See what attackers are targeting now.Read report
Firefox incorrectly accepted a newline in a HTTP/3 header, interpretting it as two separate headers. This allowed for a header splitting attack against servers using HTTP/3. This vulnerability affects Firefox < 91.0.1 and Thunderbird < 91.0.1.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade librewolfUpgrade firefoxUpgrade thunderbird | Aug 22, 2024 | Nov 3, 2021 |
| Mfsa2021 37 | — | Upgrade to Mozilla Firefox version 91.0.1Upgrade to the latest version of Mozilla Firefox | Aug 18, 2021 | Aug 16, 2021 |
| Mozilla Thunderbird | — | Upgrade to Mozilla Thunderbird version 91.0.1Upgrade to the latest version of Mozilla Thunderbird | Aug 18, 2021 | Aug 16, 2021 |
| Oracle Solaris | — | Upgrade mail/thunderbird to version 91.3.0-11.4.40.0.1.107.1 on Solaris 11.4Upgrade web/data/firefox-bookmarks to version 91.3.0-11.4.40.0.1.107.1 on Solaris 11.4Upgrade web/browser/firefox to version 91.3.0-11.4.40.0.1.107.1 on Solaris 11.4 | Dec 13, 2021 | Nov 3, 2021 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Nov 3, 2021 |
| Suse | — | Upgrade rust-cbindgenUpgrade MozillaFirefox-branding-SLEDUpgrade MozillaThunderbird-translations-otherUpgrade MozillaFirefox-develUpgrade MozillaFirefox-translations-otherUpgrade MozillaThunderbirdUpgrade MozillaFirefox-translations-commonUpgrade MozillaFirefoxUpgrade MozillaThunderbird-translations-commonUpgrade mozillafirefox-branding-sleUpgrade mozillafirefox-branding-upstream | Sep 23, 2021 | Aug 19, 2021 |
| Ubuntu | — | Upgrade firefoxUpgrade thunderbird | Aug 20, 2021 | Aug 19, 2021 |
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub