CVE-2018-5174

7.5 HIGH
Published: June 11, 2018 Modified: November 25, 2025

Description

In the Windows 10 April 2018 Update, Windows Defender SmartScreen honors the "SEE_MASK_FLAG_NO_UI" flag associated with downloaded files and will not show any UI. Files that are unknown and potentially dangerous will be allowed to run because SmartScreen will not prompt the user for a decision, and if the user is offline all files will be allowed to be opened because Windows won't prompt the user to ask what to do. Firefox incorrectly sets this flag when downloading files, leading to less secure behavior from SmartScreen. Note: this issue only affects Windows 10 users running the April 2018 update or later. It does not affect other Windows users or other operating systems. This vulnerability affects Thunderbird < 52.8, Thunderbird ESR < 52.8, Firefox < 60, and Firefox ESR < 52.8.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
http://www.securityfocus.com/bid/104136
Source: security@mozilla.org
Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1040896
Source: security@mozilla.org
Third Party Advisory VDB Entry
https://bugzilla.mozilla.org/show_bug.cgi?id=1447080
Source: security@mozilla.org
Issue Tracking Permissions Required Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2018-11/
Source: security@mozilla.org
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2018-12/
Source: security@mozilla.org
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2018-13/
Source: security@mozilla.org
Vendor Advisory
http://www.securityfocus.com/bid/104136
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1040896
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory VDB Entry
https://bugzilla.mozilla.org/show_bug.cgi?id=1447080
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Permissions Required Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2018-11/
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2018-12/
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2018-13/
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory

12 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.5%
67th percentile
Exploitation Status
Not in CISA KEV

Affected Vendors

mozilla microsoft