Verified reference description
The following technical description is credited to the CISA KEV dataset (CC0):
Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution.
Record and timeline
- Product: Microsoft — Exchange Server
- Identifier: CVE-2021-34473
- CVE record published: 2021-07-14
- Added to CISA KEV: 2021-11-03
- Reference score: 9.1/10, CVSS 3.1; provider: microsoft
- Weakness class: CWE-918
A KEV addition date is not a discovery date. CVSS describes technical severity; actual exposure and asset importance also influence remediation priority.
Defensive next steps
Match the installed Microsoft Exchange Server version and configuration against the linked technical advisory. Apply the manufacturer-approved fixed release or an explicitly documented mitigation; this profile does not guess a fixed version. Verify the patch and review relevant logs afterward. Plan a supported replacement where the product is end-of-life.
Scope and limitations
This is an awareness and defensive-prioritization profile, not a penetration test or a finding that your network is compromised. KEV membership indicates evidence of real-world exploitation. Mandatory CISA deadlines apply to entities covered by the relevant directive, not universally to every reader.
Reported versions and platforms
The table shows up to ten structured version entries from the official CVE-2021-34473 record. Original field names and values are retained deliberately. This is not an automated exposure verdict or a complete list of every product branch; use the full record and vendor advisory for a deployment decision.
| Product in record | Platform | Version fields — original values | Record status |
|---|---|---|---|
| Microsoft — Microsoft Exchange Server 2013 Cumulative Update 23 | x64-based Systems | version=15.00.0; lessThan=15.00.1497.015; versionType=custom | affected |
| Microsoft — Microsoft Exchange Server 2016 Cumulative Update 19 | x64-based Systems | version=15.01.0; lessThan=15.01.2176.012; versionType=custom | affected |
| Microsoft — Microsoft Exchange Server 2016 Cumulative Update 20 | x64-based Systems | version=15.01.0; lessThan=15.01.2242.008; versionType=custom | affected |
| Microsoft — Microsoft Exchange Server 2019 Cumulative Update 8 | x64-based Systems | version=15.02.0; lessThan=15.02.0792.013; versionType=custom | affected |
| Microsoft — Microsoft Exchange Server 2019 Cumulative Update 9 | x64-based Systems | version=15.02.0; lessThan=15.02.0858.010; versionType=custom | affected |
Full record and technical references
Turn the record into an operational decision
For Microsoft Exchange Server, record the asset, effective version, enabled feature and access path. When the reference does not map clearly to your package or branch, retain an explicit unknown status and assign follow-up rather than guessing that the system is safe.
After remediation, record the effective running version, health-check outcome and change time, not merely installation success. Evidence of compromise requires the appropriate incident-response workflow; this page does not diagnose any network as compromised or clean.
Scoring vector and scope
Vector recorded by the reference: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
CVSS is owned by FIRST and used by permission. The reference score is not a substitute for organizational risk assessment. Version data comes from the record retrieved for this review and may change when sources are updated.
