CVE-2026-55007: Microsoft Exchange Server Remote Code Execution Vulnerability

Published Sep 8, 2026
·
Updated

Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.

Other sources

Microsoft Exchange Server Remote Code Execution Vulnerability

Microsoft

Affected Software

3 affected componentsFixes available
Microsoft Exchange Server Subscription Edition RTM<15.02.2562.049
15.02.2562.049
Microsoft Exchange Server 2019=14
15.02.1544.046
Microsoft Exchange Server 2019=15
15.02.1748.051

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.02.2562.049Patch KB5121608
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.02.1544.046Patch KB5121610
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.02.1748.051Patch KB5121609

Event History

Sep 8, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·05:10 PM
Data Sourced
via MITRE·05:10 PM
DescriptionSeverity
Data Sourced
via NVD·06:17 PM
DescriptionSeverityWeakness

Frequently Asked Questions

1

Which Exchange Server deployments are identified as affected?

The affected software listed is Microsoft Exchange Server 2019 and Microsoft Exchange Server Subscription Edition RTM.

2

Does exploitation require authentication or user interaction?

The provided vector indicates no privileges are required and no user interaction is required. The vulnerability is remotely reachable over a network, although exploitation complexity is rated high.

3

What impact could successful exploitation have?

Successful exploitation can allow unauthorized remote code execution. The supplied metrics rate confidentiality, integrity, and availability impact as high.

Contact

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