VULNERABILITY INTELLIGENCE

CVE-2019-9803

CVSS score7.4 HIGH
EPSS probability0.56%
CISA KEVNot currently listed
Published2019-04-26
Last modified2026-06-17
CVSS vectorCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

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.

Weakness classification

  • CWE-346: Origin Validation Error

Primary references