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CVE-2021-33766

Published: Jul 14, 2021Updated: Oct 29, 2025 Sources: CVE List NVD BDUNVD-CWE-noinfo
7.3HIGH
NVD MITRE
EPSS Score
97.5%
Top 0.1%
CISA KEV
Active Exploitation
Since Jan 18, 2022
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Nuclei · OpenVAS

Description

Microsoft Exchange Server Information Disclosure Vulnerability

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:LI:LA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:LAvailability
Low
Open in CVSS calculator →

Weaknesses

NVD-CWE-noinfo

Affected Products

Microsoft Corp
commercial·USaka Microsoft, microsoft corporation
Microsoft Exchange Server 2019 Cumulative Update 9On-premWeb App
Enterprise Software / itsm-monitoring
Microsoft Exchange Server 2016 Cumulative Update 20On-premWeb App
Enterprise Software / itsm-monitoring
Microsoft Exchange Server 2013 Cumulative Update 23On-prem
Enterprise Software / itsm-monitoring
Microsoft Exchange Server 2016 Cumulative Update 19On-premWeb App
Enterprise Software / itsm-monitoring
Microsoft Exchange Server 2019 Cumulative Update 8On-premWeb App
Enterprise Software / itsm-monitoring
exchange serverOn-prem
Operating Systems / windows
Microsoft Exchange ServerOn-prem
Operating Systems

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:Jan 18, 2022
Remediation due:Feb 1, 2022

Required action: Apply updates per vendor instructions.

Official Patch Available
Is your org exposed to CVE-2021-33766?We'll check your whole external perimeter for exposure — free. Check my exposure

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33766
portal.msrc.microsoft.com
https://www.zerodayinitiative.com/advisories/ZDI-21-798/
zerodayinitiative.com
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33766
cisa.gov
and 3 more references View all →

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