CVE-2019-9803: mozilla firefox Origin Validation Error
Vulnerability summary
CVE-2019-9803 is a high (CVSS 7.4) Origin Validation Error vulnerability in mozilla firefox. EPSS estimates a 0.56% chance of exploitation in the next 30 days, higher than 45.4% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 4 · Related 4Timeline
- 26-04-2019PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 2 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.4HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS trend
Probability
0.56%
Chance of exploitation in the next 30 days
Percentile
45%
Versus all other CVEs
30-day change
0.00 pp
From 0.56% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu3 products
- firefox< 66.0.1+build1-0ubuntu0.14.04.1 | < 66.0+build3-0ubuntu0.16.04.2 | < 66.0+build3-0ubuntu0.18.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
Mozilla1 product
- firefox≥ unspecified, < 66 | < 66.0
2 vendors · 4 products
References
9 links- bugzilla.mozilla.org/show_bug.cgi?id=1515863X Refsource MISCIssue TrackingPermissions RequiredVendor Advisory