CVE-2021-33779 — Windows AD FS Security Feature Bypass Vulnerability

Executive Summary

None

Overview

8.1

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Security Feature Bypass

Released Jul 13 2021

Last Updated Jul 13 2021

Publicly Disclosed Yes

CISA KEV Not Listed

Known Exploits None Known

NVD CVSS 8.1 HIGH — matches MSRC

CVSS Vector

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

ATTACK VECTOR

Network

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

None

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 7.1

EPSS Score

No EPSS score available for this CVE.

View on FIRST.org

Affected Products

6 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows Server 2019	`5004244 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2019 (Server Core installation)	`5004244 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server, version 2004 (Server Core installation)	`5004237 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server, version 20H2 (Server Core Installation)	`5004237 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016	`5004238 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016 (Server Core installation)	`5004238 (Security Update)`	Important	Security Feature Bypass	Yes

Patches

3 patches

Article	Type	Restart
`5004244`	Security Update	Yes
`5004237`	Security Update	Yes
`5004238`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Microsoft has not published researcher acknowledgments for this CVE, or they are not yet reflected in our data source. Check the MSRC advisory directly for the most current credit information.

References

MSRC Advisory MITRE NVD