CVE-2023-21529highunder attackransomwareCWE-502

CVE-2023-21529: high-severity vulnerability in Microsoft Exchange Server 2013 Cumulative…

Microsoft Exchange Server Remote Code Execution Vulnerability

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63Vexday Risk Score

Prioritize patching. It under exploitation confirmed by CISA and has an official Brazilian government alert.

ssvc Actcvss 8.8epss 59%
from disclosure to weapon
Published on NVDFeb 14
CISA KEV+1154d
Official alert in Brazil

Brazil's federal government published an alert, recommendation or bulletin that cites this vulnerability.

  • CTIR Gov · ALERTA 28/2026Vulnerabilidade Crítica de Execução de Código no Microsoft Exchange Serverread on gov.br ↗
Source: CTIR Gov (GSI) and CISC Gov.br, under the CC BY-ND 3.0 license.
Action required by CISAfederal deadline: 2026-04-27

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

In short

A flaw in Microsoft Exchange Server allows attackers to execute arbitrary code on the server by sending specially crafted requests. This is critical because Exchange servers often handle sensitive business email and data.

Technical detail

Unsafe deserialization vulnerability (CWE-502) in Exchange Server allows remote code execution when processing malicious serialized objects. An attacker with network access can exploit this to achieve RCE without prior authentication.

Summary generated and translated by AI from the official description.

The full analysis of this CVE is available in Portuguese →

Microsoft Exchange Server Remote Code Execution Vulnerability
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Affected products
Microsoft · Microsoft Exchange Server 2013 Cumulative Update 23Microsoft · Microsoft Exchange Server 2016 Cumulative Update 23Microsoft · Microsoft Exchange Server 2019 Cumulative Update 11Microsoft · Microsoft Exchange Server 2019 Cumulative Update 12
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