CVE-2019-9801: mozilla firefox Improper Input Validation
Vulnerability summary
CVE-2019-9801 is a medium (CVSS 5.3) Improper Input Validation vulnerability in mozilla firefox. EPSS estimates a 1.31% chance of exploitation in the next 30 days, higher than 70.2% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 8 · Related 7Timeline
- 26-04-2019PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
Firefox will accept any registered Program ID as an external protocol handler and offer to launch this local application when given a matching URL on Windows operating systems. This should only happen if the program has specifically registered itself as a "URL Handler" in the Windows registry. *Note: This issue only affects Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.
CVSS metrics
3 scores · 2 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS trend
Probability
1.31%
Chance of exploitation in the next 30 days
Percentile
70%
Versus all other CVEs
30-day change
0.00 pp
From 1.31% 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
Mozilla3 products
- firefox≥ unspecified, < 66 | < 66.0
- firefox_esr≥ unspecified, < 60.6 | < 60.6
- thunderbird≥ unspecified, < 60.6 | < 60.6
Ubuntu2 products
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
2 vendors · 5 products
References
9 links- bugzilla.mozilla.org/show_bug.cgi?id=1527717X Refsource MISCIssue TrackingPermissions RequiredVendor Advisory