Vulnerability in Mozilla Firefox
CVE-2019-9803
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.006 (44.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 44.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Mozilla Firefox — versions unspecified
Weakness classification (CWE)
References
- www.mozilla.org/security/advisories/mfsa2019-07/ (Vendor Advisory)
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking, Vendor Advisory)
- bugzilla.mozilla.org/show_bug.cgi (Issue Tracking, Vendor Advisory)
- w3c.github.io/webappsec-upgrade-insecure-requests/ (Third Party Advisory)
Frequently asked questions
- What is CVE-2019-9803?
- CVE-2019-9803 is a high-severity vulnerability in Mozilla Firefox, classified under Origin Validation Error. CVSS score: 7.4/10. Published 2019-04-26.
- How severe is CVE-2019-9803?
- High severity. CVSS v3 base score is 7.4 out of 10.