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Microsoft Security Response CenterCVE-2026-62912

Microsoft Exchange Server Denial of Service Vulnerability

Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to deny service over a network.

Read the vendor bulletin Get alerts for Microsoft Exchange Server Subscription Edition RTM
6.5CVSS out of 10High severity
Scope

What the vendor says is affected

  • Microsoft Exchange Server Subscription Edition RTM
  • Microsoft Exchange Server 2019 Cumulative Update 15
  • Microsoft Exchange Server 2016 Cumulative Update 23
  • Microsoft Exchange Server 2019 Cumulative Update 14

Versions the vendor lists as fixed

  • 15.02.2562.046
  • 15.02.1748.049
  • 15.01.2507.072
  • 15.02.1544.044
Next step

What the vendor recommends

Install KB5121573. Install KB5121574. Install KB5121576. Install KB5121575.

Review the complete instructions on the vendor's site
Update history

What changed in later vendor updates

SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.

    • The vendor changed its remediation guidance.
Timeline

When this advisory changed

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Confirmed at the source

    Our collector saw this advisory during a later source check.

Vulnerabilities

CVEs named in this advisory

CVE-2026-62912View CVSS, KEV, EPSS, and threat context
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