CVE-2021-31207
Detail
Description
Microsoft Exchange Server Security Feature Bypass Vulnerability
Metrics
CVSS Version 4.0
CVSS Version 3.x
CVSS Version 2.0
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.
CVSS 3.x Severity and Vector Strings:
CNA: Microsoft Corporation
Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0 Severity and Vector Strings:
Vector:
(AV:N/AC:L/Au:S/C:P/I:P/A:P)
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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 Security Feature Bypass Vulnerability
11/03/2021
11/17/2021
Apply updates per vendor instructions.
Weakness Enumeration
CWE-ID
CWE Name
Source
CWE-434
Unrestricted Upload of File with Dangerous Type
NIST
CISA-ADP
Change History
16 change records found show changes
Modified Analysis by NIST 10/30/2025 3:40:19 PM
Action
Type
Old Value
New Value
Added
Reference Type
CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31207 Types: US Government Resource
CVE Modified by CISA-ADP 10/21/2025 8:17:35 PM
Action
Type
Old Value
New Value
Added
Reference
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31207
CVE Modified by CISA-ADP 10/21/2025 4:18:35 PM
Action
Type
Old Value
New Value
Removed
Reference
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31207
CVE Modified by CISA-ADP 10/21/2025 3:19:06 PM
Action
Type
Old Value
New Value
Added
Reference
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31207
Modified Analysis by NIST 3/13/2025 12:41:49 PM
Action
Type
Old Value
New Value
CVE Modified by CISA-ADP 2/04/2025 2:15:24 PM
Action
Type
Old Value
New Value
Added
CWE
CWE-434
CVE Modified by CVE 11/21/2024 1:05:18 AM
Action
Type
Old Value
New Value
Added
Reference
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html
Added
Reference
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207
Added
Reference
https://www.zerodayinitiative.com/advisories/ZDI-21-819/
Modified Analysis by NIST 7/26/2024 3:25:27 PM
Action
Type
Old Value
New Value
Added
CVSS V3.1
NIST AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Removed
CVSS V3.1
NIST AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVE Modified by Microsoft Corporation 5/14/2024 4:59:11 AM
Action
Type
Old Value
New Value
CWE Remap by NIST 8/08/2023 10:21:49 AM
Action
Type
Old Value
New Value
Changed
CWE
CWE-22
CWE-434
CVE Modified by Microsoft Corporation 8/01/2023 8:15:14 PM
Action
Type
Old Value
New Value
Added
CVSS V3.1
Microsoft Corporation AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
CWE Remap by NIST 7/12/2022 1:42:04 PM
Action
Type
Old Value
New Value
Changed
CWE
NVD-CWE-noinfo
CWE-22
Modified Analysis by NIST 9/21/2021 1:45:53 PM
Action
Type
Old Value
New Value
Changed
Reference Type
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html No Types Assigned
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html Exploit, Third Party Advisory, VDB Entry
Changed
Reference Type
https://www.zerodayinitiative.com/advisories/ZDI-21-819/ No Types Assigned
https://www.zerodayinitiative.com/advisories/ZDI-21-819/ Third Party Advisory, VDB Entry
CVE Modified by Microsoft Corporation 8/20/2021 2:15:07 PM
Action
Type
Old Value
New Value
Added
Reference
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html [No Types Assigned]
CVE Modified by Microsoft Corporation 7/19/2021 6:15:07 AM
Action
Type
Old Value
New Value
Added
Reference
https://www.zerodayinitiative.com/advisories/ZDI-21-819/ [No Types Assigned]
Initial Analysis by NIST 5/18/2021 4:40:21 PM
Action
Type
Old Value
New Value
Added
CVSS V3.1
NIST AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Added
CVSS V2
NIST (AV:N/AC:L/Au:S/C:P/I:P/A:P)
Added
CWE
NIST NVD-CWE-noinfo
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-2021-31207 No Types Assigned
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207 Patch, Vendor Advisory
Quick Info
CVE Dictionary Entry: CVE-2021-31207 NVD
Published Date: 05/11/2021 NVD
Last Modified: 10/30/2025
Source: Microsoft Corporation