CVE-2026-45500Network attack vector

Spoofing via undisclosed cross-site scripting

Published Jun 9, 2026 · Updated Jun 9, 2026

Cross-site scripting in Microsoft Exchange Server allows remote attackers to spoof web content through network requests. Microsoft has not disclosed the affected web component or how untrusted input reaches generated pages without effective neutralization. Exploitation requires user interaction and can expose or alter browser-visible content, but it does not interrupt the Exchange service.

CVSS severity6.1
Medium
EPSS probability0.38%
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 allows remote attackers to spoof web content through network requests. Microsoft has not disclosed the affected web component or how untrusted input reaches generated pages without effective neutralization. Exploitation requires user interaction and can expose or alter browser-visible content, but it does not interrupt the Exchange service.

The record

CVE
CVE-2026-45500
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
Microsoft
Product
Microsoft Exchange Server 2019 Cumulative Update 14
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 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 <15.02.1544.041

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Exchange Server 2019 Cumulative Update 14version=15.02.0.0 <15.02.1544.041
Microsoft · Microsoft Exchange Server Subscription Edition RTMversion=15.02.0.0 <15.02.2562.043
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 23version=15.01.0.0 <15.01.2507.069
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 15version=15.02.0.0 <15.02.1748.046

Published CVSS scores

6.1MicrosoftCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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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