CISA Known Exploited Vulnerability
This vulnerability is actively exploited in the wild and listed in the CISA Known Exploited Vulnerabilities catalog.
Remediation Deadline: Apr 27, 2026
Description
Microsoft Exchange Server contains a deserialization of untrusted data that allows an authenticated attacker to achieve remote code execution.
Required Action
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529 ; https://nvd.nist.gov/vuln/detail/CVE-2023-21529
Risk Assessment
ELEVATEDIn CISA KEV
Details
- Severity
- High
- CISA KEV
- Yes
- Ransomware
- Unknown
- Articles
- 0
Timeline
Published
Apr 13, 2026
Added to KEV
Apr 13, 2026
Remediation Due
Apr 27, 2026