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URL: https://nvd.nist.gov/vuln/detail/CVE-2021-33766

⇱ NVD - CVE-2021-33766

  1. Vulnerabilities

CVE-2021-33766 Detail

Description

Microsoft Exchange Server Information Disclosure Vulnerability


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33766 CVE, Microsoft Corporation Patch  Vendor Advisory 
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33766 CISA-ADP US Government Resource 
https://www.zerodayinitiative.com/advisories/ZDI-21-798/ CVE, Microsoft Corporation Third Party Advisory  VDB Entry 

This CVE is in CISA's Known Exploited Vulnerabilities Catalog

Reference CISA's BOD 22-01 and Known Exploited Vulnerabilities Catalog for further guidance and requirements.

Vulnerability Name Date Added Due Date Required Action
Microsoft Exchange Server Information Disclosure 01/18/2022 02/01/2022 Apply updates per vendor instructions.

Weakness Enumeration

CWE-ID CWE Name Source
NVD-CWE-noinfo Insufficient Information 👁 cwe source acceptance level
NIST  

Known Affected Software Configurations Switch to CPE 2.2

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Denotes Vulnerable Software
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Change History

13 change records found show changes

CVE Modified by CISA-ADP 6/16/2026 11:55:11 PM

Action Type Old Value New Value
Added SSVC 
{"timestamp":"2025-02-04T19:07:59.976278Z","id":"CVE-2021-33766","options":[{"exploitation":"active"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}

CVE Modified by Microsoft Corporation 6/16/2026 11:55:11 PM

Action Type Old Value New Value
Added Affected 
[{"vendor":"Microsoft","product":"Microsoft Exchange Server 2019 Cumulative Update 9","cpes":["cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:*"],"platforms":["x64-based Systems"],"versions":[{"version":"15.02.0","lessThan":"15.02.0858.010","versionType":"custom","status":"affected"}]},{"vendor":"Microsoft","product":"Microsoft Exchange Server 2016 Cumulative Update 20","cpes":["cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:*"],"platforms":["x64-based Systems"],"versions":[{"version":"15.01.0","lessThan":"15.01.2242.008","versionType":"custom","status":"affected"}]},{"vendor":"Microsoft","product":"Microsoft Exchange Server 2013 Cumulative Update 23","cpes":["cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*"],"platforms":["x64-based Systems"],"versions":[{"version":"15.00.0","lessThan":"15.00.1497.015","versionType":"custom","status":"affected"}]},{"vendor":"Microsoft","product":"Microsoft Exchange Server 2016 Cumulative Update 19","cpes":["cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*"],"platforms":["x64-based Systems"],"versions":[{"version":"15.01.0","lessThan":"15.01.2176.012","versionType":"custom","status":"affected"}]},{"vendor":"Microsoft","product":"Microsoft Exchange Server 2019 Cumulative Update 8","cpes":["cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*"],"platforms":["x64-based Systems"],"versions":[{"version":"15.02.0","lessThan":"15.02.0792.013","versionType":"custom","status":"affected"}]}]

Modified Analysis by NIST 10/29/2025 12:47:15 PM

Action Type Old Value New Value
Added Reference Type 
CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33766 Types: US Government Resource

CVE Modified by CISA-ADP 10/21/2025 8:17:37 PM

Action Type Old Value New Value
Added Reference 
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33766

CVE Modified by CISA-ADP 10/21/2025 4:18:37 PM

Action Type Old Value New Value
Removed Reference 
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33766

CVE Modified by CISA-ADP 10/21/2025 3:19:07 PM

Action Type Old Value New Value
Added Reference 
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33766

Modified Analysis by NIST 3/07/2025 5:01:06 PM

Action Type Old Value New Value
Added CWE 
NVD-CWE-noinfo
Removed CWE 
CWE-287

CVE Modified by CVE 11/21/2024 1:09:32 AM

Action Type Old Value New Value
Added Reference 
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33766
Added Reference 
https://www.zerodayinitiative.com/advisories/ZDI-21-798/

Modified Analysis by NIST 7/24/2024 12:45:35 PM

Action Type Old Value New Value

CVE Modified by Microsoft Corporation 5/14/2024 5:11:39 AM

Action Type Old Value New Value

CVE Modified by Microsoft Corporation 12/28/2023 6:15:20 PM

Action Type Old Value New Value
Changed Description 
Microsoft Exchange Information Disclosure Vulnerability


 
Microsoft Exchange Server Information Disclosure Vulnerability
Added CVSS V3.1 
Microsoft Corporation AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Initial Analysis by NIST 7/16/2021 10:41:29 AM

Action Type Old Value New Value
Added CVSS V3.1 
NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Added CVSS V2 
NIST (AV:N/AC:L/Au:N/C:P/I:N/A:N)
Added CWE 
NIST CWE-287
Added CPE Configuration 
OR
 *cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*
 *cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*
 *cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:*
 *cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*
 *cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:*
Changed Reference Type 
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33766 No Types Assigned


 
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33766 Patch, Vendor Advisory
Changed Reference Type 
https://www.zerodayinitiative.com/advisories/ZDI-21-798/ No Types Assigned


 
https://www.zerodayinitiative.com/advisories/ZDI-21-798/ Third Party Advisory, VDB Entry

CVE Modified by Microsoft Corporation 7/15/2021 3:15:08 AM

Action Type Old Value New Value
Added Reference 
https://www.zerodayinitiative.com/advisories/ZDI-21-798/ [No Types Assigned]

Quick Info

CVE Dictionary Entry:
CVE-2021-33766
NVD Published Date:
07/14/2021
NVD Last Modified:
06/16/2026
Source:
Microsoft Corporation