High [CVE-2023-21529] Microsoft Exchange Server Remote Code Execution Vulnerability
This high-severity Microsoft Server advisory covers CVE-2023-21529 affecting Microsoft Exchange Server 2013 Cumulative Update 23, Microsoft Exchange Server 2016 Cumulative Update 23, Microsoft Exchange Server 2019 Cumulative Update 11.
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Summary
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected products named by the advisory: Microsoft Exchange Server 2013 Cumulative Update 23; Microsoft Exchange Server 2016 Cumulative Update 23; Microsoft Exchange Server 2019 Cumulative Update 11; Microsoft Exchange Server 2019 Cumulative Update 12.
CISA Known Exploited Vulnerability
- Listed:
- Apr 13, 2026 · federal remediation due Apr 27, 2026
- Required action:
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Ransomware use:
- Known
KEV is a prioritization signal from CISA — remediation detail still comes from the vendor advisory.
- Microsoft Exchange Server 2013 Cumulative Update 23 15.00.0 before 15.00.1497.047
- Microsoft Exchange Server 2016 Cumulative Update 23 15.01.0 before 15.01.2507.021
- Microsoft Exchange Server 2019 Cumulative Update 11 15.02.0 before 15.02.0986.041
- Microsoft Exchange Server 2019 Cumulative Update 12 15.02.0 before 15.02.1118.025
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
- 15.00.1497.047
- 15.01.2507.021
- 15.02.0986.041
- 15.02.1118.025
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation
Upgrade to a fixed release: 15.00.1497.047, 15.01.2507.021, 15.02.0986.041, 15.02.1118.025. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Discussion(0)
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