Spoofing via untrusted data deserialization
Published Jan 10, 2023 · Updated Feb 28, 2025
Deserialization of untrusted data in affected Microsoft Exchange Server 2016 and 2019 builds allows remote authenticated users to spoof content. Microsoft maps the flaw to untrusted-data deserialization and introduced signing for PowerShell serialization payloads, but it has not tied the CVE to a specific code path. Exploitation requires low privileges and adjacent-network access; Microsoft has not published the exact spoofed artifact or operation.
Summary
What happened
Deserialization of untrusted data in affected Microsoft Exchange Server 2016 and 2019 builds allows remote authenticated users to spoof content. Microsoft maps the flaw to untrusted-data deserialization and introduced signing for PowerShell serialization payloads, but it has not tied the CVE to a specific code path. Exploitation requires low privileges and adjacent-network access; Microsoft has not published the exact spoofed artifact or operation.
The record
- CVE
- CVE-2023-21745
- Published
- Jan 10, 2023
- Updated
- Feb 28, 2025
- Vendor
- Microsoft
- Product
- Microsoft Exchange Server 2019 Cumulative Update 12
- Classifications
- CWE-502
- Attack vector
- adjacent
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 10, 2023CVE publishedPublication date reported by the CVE source.
- Feb 28, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=15.02.0 <15.02.1118.021
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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