CVE-2021-34473

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2021-34473
Microsoft Exchange Server Remote Code Execution Vulnerability

9.1 /10

CVSS v3 : CRITICAL

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

10.0 /10

CVSS v2.0 : HIGH

V2 Legend

Vector : AV:N/AC:L/Au:N/C:C/I:C/A:C

Exploitability : 10.0 / Impact : 10.0

Access Vector NETWORK

Access Complexity LOW

Authentication NONE

Confidentiality Impact COMPLETE

Integrity Impact COMPLETE

Availability Impact COMPLETE

References
Link Resource
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html Exploit Third Party Advisory VDB Entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473 Patch Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-821/ Third Party Advisory VDB Entry
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html Exploit Third Party Advisory VDB Entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473 Patch Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-821/ Third Party Advisory VDB Entry
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473 US Government Resource
Configurations

Configuration 1 (hide)

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:*:*:*:*:*:*
History

29 Oct 2025, 16:46

Type Values Removed Values Added
References () https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473 - () https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473 - US Government Resource

22 Oct 2025, 00:17

Type Values Removed Values Added
References
  • () https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473 -

21 Oct 2025, 20:18

Type Values Removed Values Added
References
  • {'url': 'https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473', 'source': '134c704f-9b21-4f2e-91b3-4a467353bcc0'}

21 Oct 2025, 19:19

Type Values Removed Values Added
References
  • () https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473 -

21 Nov 2024, 06:10

Type Values Removed Values Added
References () http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html - Exploit, Third Party Advisory, VDB Entry () http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html - Exploit, Third Party Advisory, VDB Entry
References () https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473 - Patch, Vendor Advisory () https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473 - Patch, Vendor Advisory
References () https://www.zerodayinitiative.com/advisories/ZDI-21-821/ - Third Party Advisory, VDB Entry () https://www.zerodayinitiative.com/advisories/ZDI-21-821/ - Third Party Advisory, VDB Entry

28 Dec 2023, 23:15

Type Values Removed Values Added
CVSS v2 : 10.0
v3 : 9.8 		v2 : 10.0
v3 : 9.1
Summary Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-31196, CVE-2021-31206. Microsoft Exchange Server Remote Code Execution Vulnerability

12 Jul 2022, 17:42

Type Values Removed Values Added
CWE NVD-CWE-noinfo CWE-918

21 Sep 2021, 17:38

Type Values Removed Values Added
References (MISC) http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html - (MISC) http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html - Exploit, Third Party Advisory, VDB Entry
References (MISC) https://www.zerodayinitiative.com/advisories/ZDI-21-821/ - Third Party Advisory (MISC) https://www.zerodayinitiative.com/advisories/ZDI-21-821/ - Third Party Advisory, VDB Entry

20 Aug 2021, 18:15

Type Values Removed Values Added
References
  • (MISC) http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html -

19 Jul 2021, 15:35

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown 		v2 : 10.0
v3 : 9.8
CWE NVD-CWE-noinfo
CPE cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:*
References
  • (MISC) https://www.zerodayinitiative.com/advisories/ZDI-21-821/ - Third Party Advisory
References (MISC) https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473 - (MISC) https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473 - Patch, Vendor Advisory

14 Jul 2021, 19:14

Type Values Removed Values Added
New CVE
Information

Published : 2021-07-14 18:15

Updated : 2025-10-29 16:46

NVD link : CVE-2021-34473

Mitre link : CVE-2021-34473

CVE.ORG link : CVE-2021-34473

JSON object : View

Products Affected

microsoft

  • exchange_server
CWE
CWE-918

Server-Side Request Forgery (SSRF)