High severity7.4NVD Advisory· Published Apr 26, 2019· Updated Jun 17, 2026
CVE-2019-9803
CVE-2019-9803
Description
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
5cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*range: <66.0
- (no CPE)range: <66
- (no CPE)range: unspecified
- osv-coords2 versionspkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/firefox-esr&distro=openSUSE%20Tumbleweed
< 92.0-1.2+ 1 more
- (no CPE)range: < 92.0-1.2
- (no CPE)range: < 128.5.1-1.1
Patches
Vulnerability mechanics
References
4- bugzilla.mozilla.org/show_bug.cginvdIssue TrackingVendor Advisory
- bugzilla.mozilla.org/show_bug.cginvdIssue TrackingPermissions RequiredVendor Advisory
- w3c.github.io/webappsec-upgrade-insecure-requests/nvdThird Party Advisory
- www.mozilla.org/security/advisories/mfsa2019-07/nvdVendor Advisory
News mentions
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