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The Upgrade-Insecure-Requests (UIR) specification states that if UIR is enabled through Content Security Policy (CSP), navigation to a same-origin URL must be upgraded to HTTPS. Firefox will incorrectly navigate to an HTTP URL rather than perform the security upgrade requested by the CSP in some circumstances, allowing for potential man-in-the-middle attacks on the linked resources. This vulnerability affects Firefox < 66.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Arch Linux | — | Upgrade to the latest version of Arch Linux | Jul 11, 2025 | Apr 26, 2019 |
| Freebsd | — | Upgrade thunderbirdUpgrade firefoxUpgrade waterfoxUpgrade seamonkeyUpgrade linux-firefoxUpgrade linux-seamonkeyUpgrade libxulUpgrade firefox-esrUpgrade linux-thunderbird | Mar 20, 2019 | Mar 19, 2019 |
| Mfsa2019 07 | — | Upgrade to Mozilla Firefox version 66.0Upgrade to the latest version of Mozilla Firefox | Mar 20, 2019 | Mar 19, 2019 |
| Ubuntu | — | Upgrade firefox | Apr 1, 2019 | Mar 19, 2019 |
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