Is CVE-2018-5174 being actively exploited?

It is not currently in CISA's KEV catalog. Its EPSS exploitation probability is 2%.

What products does CVE-2018-5174 affect?

Tracked products affected include Windows 10. Check the version you run to see whether it is affected.

How do I fix CVE-2018-5174?

Apply the vendor fix promptly. Upgrade affected products to a fixed version.

CVE-2018-5174

Q: What is CVE-2018-5174?

CVE-2018-5174 is a high-severity software vulnerability with a CVSS score of 7.5. 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 becau

HIGH severity · CVSS 7.5

7.5CVSS HIGH

Summary

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.

Impact & exploitability

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

Confidentiality impactNone

Integrity impactHigh

Availability impactNone

Exploit probability (EPSS)2%

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products we track (1)

Windows 10

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Additional information

NVD record
https://www.mozilla.org/security/advisories/mfsa2018-11/Advisory
https://www.mozilla.org/security/advisories/mfsa2018-12/Advisory
https://www.mozilla.org/security/advisories/mfsa2018-13/Advisory
http://www.securityfocus.com/bid/104136Advisory
http://www.securitytracker.com/id/1040896Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1447080Advisory