CVE-2019-9794

Name: CVE-2019-9794
Creator: NVD / NIST
Published: 2019-04-26T17:29:02.087+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 1.77%

Last modified Jun 17, 2026

CVE-2019-9794 is a vulnerability of currently unknown severity. A vulnerability was discovered where specific command line arguments are not properly discarded during Firefox invocation as a shell handler for URLs. This could be used to retrieve and execute files whose location is supplied through these command line arguments if Firefox is configured as the default URI handler for a given URI scheme in third party applications and these applications insufficiently sanitize URL data. EPSS estimates a 1.77% chance of exploitation in the next 30 days.

Description

A vulnerability was discovered where specific command line arguments are not properly discarded during Firefox invocation as a shell handler for URLs. This could be used to retrieve and execute files whose location is supplied through these command line arguments if Firefox is configured as the default URI handler for a given URI scheme in third party applications and these applications insufficiently sanitize URL data. *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.

Metrics

EPSS Probability

1.77%

75.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-88

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 60.6.0
Mozilla	Firefox	< 66.0
Mozilla	Thunderbird	< 60.6.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1530103Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-07/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-08/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-11/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1530103Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-07/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-08/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-11/Vendor Advisory

Timeline

Published: Apr 26, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-9794?

How severe is CVE-2019-9794?

Severity scoring for CVE-2019-9794 is pending analysis. The EPSS model estimates a 1.77% probability of exploitation in the next 30 days.

How do I fix CVE-2019-9794?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-9794?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST