CVE-2018-5174
In the Windows 10 April 2018 Update, Windows Defender SmartScreen honors the "SEE_MASK_FLAG_NO_UI" flag associated with downloaded files…
- 7.5HighCVSS base score
- 1.8%Exploitation in 30 daysEPSS · top 21% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By mozilla
- 5 months later
· 5 months later
Published
- 6 years later
· 6 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.0 | High7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 1.8% · top 21% of all CVEs (9 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
- affected unspecified – < 52.8
- affected unspecified – < 52.8
- affected unspecified – < 60
- affected unspecified – < 52.8
References
6
- https://bugzilla.mozilla.org/show_bug.cgi?id=1447080 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://www.mozilla.org/security/advisories/mfsa2018-13/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://www.mozilla.org/security/advisories/mfsa2018-11/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- 1040896 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- https://www.mozilla.org/security/advisories/mfsa2018-12/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- 104136 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2018-16959 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2018-5174)Record last updated .