CVE-2018-8340
A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor…
- 6.5MediumCVSS base score
- 7.9%Exploitation in 30 daysEPSS · top 5.2% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor authentication requests, aka "AD FS Security Feature Bypass Vulnerability." This affects Windows Server 2016, Windows Server 2012 R2, Windows 10 Servers.
Timeline
ID reserved
By microsoft
- 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 | Medium6.5 | CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 7.9% · top 5.2% of all CVEs (9 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Affected products
Microsoft · Windows Server 2016
- affected (Server Core installation)
Microsoft · Windows Server 2012 R2
- affected (Server Core installation)
Microsoft · Windows 10 Servers
- affected version 1709 (Server Core Installation)
- affected version 1803 (Server Core Installation)
References
3
- 1041474 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- 105029 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8340 (opens in a new tab)x_refsource_CONFIRMx_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-2018-19991 (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-2018-8340)Record last updated .