The Upgrade-Insecure-Requests (UIR) specification states that if UIR is enabled through Content Security Policy (CSP), navigation to a…

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.

Scores

EPSS (exploitation in 30 days)

0.56% · top 53% of all CVEs (5 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.4.

Weakness

• Upgrade-Insecure-Requests incorrectly enforced for same-origin navigation
• CWE-346 (opens in a new tab)All about CWE-346 and its CVEs

Affected products

• Mozilla · Firefox

  • affected unspecified – < 66

References (4)

• https://www.mozilla.org/security/advisories/mfsa2019-07/ (opens in a new tab)x_refsource_MISCx_transferred
• https://bugzilla.mozilla.org/show_bug.cgi?id=1515863 (opens in a new tab)x_refsource_MISCx_transferred
• https://bugzilla.mozilla.org/show_bug.cgi?id=1437009 (opens in a new tab)x_refsource_MISCx_transferred
• https://w3c.github.io/webappsec-upgrade-insecure-requests/ (opens in a new tab)x_refsource_MISCx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2019-9803](https://trackcve.app/badge/CVE-2019-9803.svg)](https://trackcve.app/cve/CVE-2019-9803)

Record last updated 4 Aug 2024, 22:01 UTC.