AEGLIX vulnerability intelligence
CVE-2021-34473
CRITICAL · CVSS 9.1 · Analyzed
Published: 2021-07-14 · Updated: 2026-08-10 · Source: NVD
Vulnerability overview
Microsoft Exchange Server Remote Code Execution Vulnerability
Severity and scoring
- CVSS score
- 9.1 · CRITICAL
- CVSS version
- 3.1
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Weaknesses
- CWE-918
CVSS measures technical severity; it does not establish whether this vulnerability is being exploited in your environment.
Known exploitation and remediation
Listed in CISA’s Known Exploited Vulnerabilities catalog.
- Affected product
- Microsoft · Exchange Server
- Added to catalog
- 2021-11-03
- Required action
- Apply updates per vendor instructions.
- CISA remediation due date
- 2021-11-17
CISA deadlines apply to the organizations covered by its directives. Confirm your own remediation requirements.
Verify affected versions and patch availability in the vendor advisory before making changes.
Affected products and versions
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:*:*:*:*:*:*
These are NVD CPE applicability entries. Some products depend on configuration conditions; consult the official record to confirm applicability.
Advisories and references
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34473
Patch · Vendor Advisory
- 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