CVE-2023-21529
highpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.593 · 99 %ileDEEURUUSadded 2026-04-13remediate by 2026-04-27
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.
EPSS · scored 2026-10-26
Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedMicrosoft Exchange Server 2013 Cumulative Update 23msrc_csaf
15.00.1497.047:Security Update:https://support.microsoft.com/help/5023038
https://support.microsoft.com/help/5023038 - FixedMicrosoft Exchange Server 2016 Cumulative Update 23msrc_csaf
15.01.2507.021:Security Update:https://support.microsoft.com/help/5023038
https://support.microsoft.com/help/5023038 - FixedMicrosoft Exchange Server 2019 Cumulative Update 11msrc_csaf
15.02.0986.041:Security Update:https://support.microsoft.com/help/5023038
https://support.microsoft.com/help/5023038 - FixedMicrosoft Exchange Server 2019 Cumulative Update 12msrc_csaf
15.02.1118.025:Security Update:https://support.microsoft.com/help/5023038
https://support.microsoft.com/help/5023038
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (23)
Products and version ranges known to be affected.
- Microsoft Exchange Server 2013 Cumulative Update 23all versionscert_bundDEcpe:/a:microsoft:exchange_server_2013::cumulative_update_23
- Microsoft Exchange Server 2016 Cumulative Update 23all versionscert_bundDEcpe:/a:microsoft:exchange_server_2016:cumulative_update_23
- Microsoft Exchange Server 2019 Cumulative Update 11all versionscert_bundDEcpe:/a:microsoft:exchange_server_2019:cumulative_update_11
- Microsoft Exchange Server 2019 Cumulative Update 12all versionscert_bundDEcpe:/a:microsoft:exchange_server_2019:cumulative_update_12
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2023-0368Microsoft Exchange: Mehrere Schwachstellen ermöglichen CodeausführungDeutsch2023-02-14csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Microsoft Exchange Server 2013, Microsoft Exchange Server 2016 und Microsoft Exchange Server 2019 ausnutzen, um beliebigen Programmcode auszuführen.
- msrc_CVE-2023-21529Microsoft Exchange Server Remote Code Execution Vulnerability2023-02-14csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (7)
External citations — patches, advisories, analysis.
- https://cxsecurity.com/cveshow/CVE-2023-21529/cnnvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2023-21529cnnvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529enisa_euvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529PatchVendor Advisorynvd
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21529US Government Resourcenvd
- https://www.microsoft.com/en-us/security/blog/2026/04/06/storm-1175-focuses-gaze-on-vulnerable-web-facing-assets-in-high-tempo-medusa-ransomware-operations/Technical Descriptionnvd
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