HOMEVULNERABILITIESCVE-2019-9794
CRITICAL

CVE-2019-9794

CWE-88Published: April 26, 2019· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2019-9794 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Microsoft1 product(s)
windows
Mozilla2 product(s)
firefoxthunderbird
Source: NVD CPE · 3 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://bugzilla.mozilla.org/show_bug.cgi?id=1530103
ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2019-07/
ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2019-08/
ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2019-11/
ADVISORYhttps://bugzilla.mozilla.org/show_bug.cgi?id=1530103
ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2019-07/
ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2019-08/
ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2019-11/

All References (8)

→
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

Quick Facts

CVE IDCVE-2019-9794
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-88
CISA KEVNo
Affected2 vendor(s)
PublishedApr 26, 2019

Related CVEs (CWE-88)

CVE-1999-0113
10.0
CVE-2026-57572
10.0
CVE-2007-0882
10.0
CVE-2004-0480
10.0
CVE-2026-47365
9.9
CVE-2026-44450
9.9

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2019-9794 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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