CVE-2026-69356Network attack vector

Unauthenticated spoofing via undisclosed cross-site scripting

Published Sep 8, 2026 · Updated Sep 10, 2026

Cross-site scripting in Microsoft Exchange Server before the listed September 2026 builds allows remote attackers to spoof web content. Microsoft has not disclosed the affected web component, attacker-controlled input, or output-encoding failure that permits script-capable content to reach a user's browser. Exploitation requires no Exchange privileges but does require user interaction; successful attacks can expose or alter browser-accessible data without interrupting the server.

CVSS severity9.3
Critical
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Microsoft Exchange Server before the listed September 2026 builds allows remote attackers to spoof web content. Microsoft has not disclosed the affected web component, attacker-controlled input, or output-encoding failure that permits script-capable content to reach a user's browser. Exploitation requires no Exchange privileges but does require user interaction; successful attacks can expose or alter browser-accessible data without interrupting the server.

The record

CVE
CVE-2026-69356
Published
Sep 8, 2026
Updated
Sep 10, 2026
Vendor
Microsoft
Product
Microsoft Exchange Server 2019 Cumulative Update 14
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=15.02.0.0 <15.02.1544.046

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Exchange Server 2019 Cumulative Update 14version=15.02.0.0 <15.02.1544.046
Microsoft · Microsoft Exchange Server Subscription Edition RTMversion=15.02.0.0 <15.02.2562.049
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 23version=15.01.0.0 <15.01.2507.073
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 15version=15.02.0.0 <15.02.1748.051

Published CVSS scores

9.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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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