Microsoft Security Response CenterCVE-2026-69355

Microsoft Exchange Server Remote Code Execution Vulnerability

External control of file name or path in Microsoft Exchange Server allows an authorized attacker to execute code over a network.

Read the vendor bulletin Get alerts for Microsoft Exchange Server 2019 Cumulative Update

8.8CVSS out of 10High severity

Scope

What the vendor says is affected

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

Versions the vendor lists as fixed

15.02.1748.051
15.02.1544.046
15.01.2507.073
15.02.2562.049

Next step

What the vendor recommends

Install KB5121609. Install KB5121610. Install KB5121611. Install KB5121608.

Review the complete instructions on the vendor's site

Timeline

When this advisory changed

Sep 8, 2026 at 7:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
Sep 8, 2026 at 7:15 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.
Sep 13, 2026 at 2:40 AM UTC
Confirmed at the source
Our collector saw this advisory during a later source check.

Vulnerabilities

CVEs named in this advisory

CVE-2026-69355View CVSS, KEV, EPSS, and threat context

Source

Start with the vendor's bulletin

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Vendor: Microsoft Security Response Center
Advisory ID: CVE-2026-69355
Last source check: Sep 13, 2026 at 2:40 AM UTC

Open the official bulletin How SecurityAlert builds this record

Your environment

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Read the vendor's prerequisites and exceptions.
Test the update or mitigation through your normal change process.

Watch Microsoft Exchange Server 2019 Cumulative Update

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What the vendor says is affected

Versions the vendor lists as fixed

What the vendor recommends

When this advisory changed

CVEs named in this advisory

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