CVE-2021-33779 json
Windows AD FS Security Feature Bypass Vulnerability
published 2021-07-14 5 y ago modified 2026-08-10 2 mo ago also EUVD-2021-20456
- cvss
- 8.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.4%
- EPSS 2.4% chance of exploitation in 30 days, percentile 84%
- public exploits
- 0
- none known
Summary
Windows AD FS Security Feature Bypass Vulnerability
Patch / fix
- Microsoft Windows Server 2016 10.0.14393.4530
- Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.4530
- Microsoft Windows Server 2019 10.0.17763.2061
- Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.2061
- Microsoft Windows Server version 2004 10.0.19041.1110
- Microsoft Windows Server version 20H2 10.0.19042.1110
Exploit prediction
2.44% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C |
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N |
| NVD | 2.0 | 5.5 | AV:N/AC:L/Au:S/C:P/I:P/A:N |
Affected products
- Microsoft Windows Server 2016
- Microsoft Windows Server 2016 (Server Core installation)
- Microsoft Windows Server 2019
- Microsoft Windows Server 2019 (Server Core installation)
- Microsoft Windows Server version 2004
- Microsoft Windows Server version 20H2
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2021-33779
vendor-advisory, patch
-
portal.msrc.microsoft.com
/en-US/security-guidance/advisory/CVE-2021-33779
patch, vendor-advisory
Sources
- CVE List CVE-2021-33779
- NVD CVE-2021-33779
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.