Exchange ServerApplication · Microsoft

CVE-2026-47631

MEDIUM · 5.4 CVSS v3.1 Published 2026-06-09
Fix available
A fix is available. Upgrade to 15.02.2562.043 or later.
See remediation →
61/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.

In the news

Third-party coverage
Trending covered by 1 outlet this week · latest 2mo ago

Surfaced from public web coverage — external links open in a new tab.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Cross-site scripting (XSS) vulnerability in Microsoft Exchange Server where improper input neutralization allows injection of malicious scripts into web pages generated by the server. The CVSS vector indicates network-exploitable XSS with low attack complexity, requiring user interaction. The specific impact described is spoofing, suggesting the attacker could impersonate legitimate users or entities through the injected scripts.

MitigationApply Microsoft security patches for Exchange Server when available; implement input validation and output encoding on Exchange web interfaces; consider deploying Microsoft Defender for Office 365 for additional protection against XSS-based attacks.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Exchange ServerApplication
Affected:= 2016= 2019
Exchange Server Subscription EditionApplication
Affected:< 15.02.2562.043

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Exchange Server version
    Open Exchange Management Shell and run: Get-ExchangeServer | Select-Object Name, AdminDisplayVersion, ExchangeVersion
    Affected if Version matches 2016 or 2019, or is Subscription Edition with build number less than 15.02.2562.043 (build shown as like 15.2.xxxx.xx)
  2. Verify exact build number for Subscription Edition
    Run Get-ExchangeServer | Format-List to see the full build version string; compare the numeric portion against 15.02.2562.043
    Affected if Build number is less than 15.02.2562.043
  3. Confirm web interfaces are accessible
    Verify Exchange OWA (Outlook on the web) or ECP endpoints are reachable: Test-NetConnection -ComputerName <server> -Port 443 ; check if /owa and /ecp virtual directories respond
    Affected if Web interfaces are exposed and accessible without additional authentication controls isolating them
  4. Check for suspicious entries in Exchange logs
    Review IIS logs under C:\inetpub\logs\LogFiles for unusual URL patterns in /owa or /ecp paths that may indicate XSS exploitation attempts
    Affected if Logs contain encoded script tags or unexpected characters in request parameters targeting webmail endpoints

Your Exchange Server is affected if it is version 2016, 2019, or Subscription Edition with build below 15.02.2562.043 AND the web interfaces are accessible to potential attackers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 15.02.2562.043 or later
Fixed in 15.02.2562.043
Interim mitigation

Apply Microsoft security patches for Exchange Server when available; implement input validation and output encoding on Exchange web interfaces; consider deploying Microsoft Defender for Office 365 for additional protection against XSS-based attacks.

Recommended fix Moderate confidence

Microsoft Exchange Server build 15.02.2562.043 or later (for Exchange 2019); corresponding patched build for Exchange 2016

  1. 1. Identify your current Microsoft Exchange Server build version by running: Get-ExchangeServer | Format-List Name, Edition, AdminDisplayVersion
  2. 2. Review Microsoft Security Response Center (msrc.microsoft.com) for the specific security update corresponding to CVE-2026-47631
  3. 3. Apply the relevant security update for your Exchange Server version (2016, 2019, or Subscription Edition)
  4. 4. After applying the update, verify the installation was successful by checking the build version matches the patched release
  5. 5. Test critical Exchange services (OWA, ECP, Outlook on the web) to confirm normal operation
Caveat Standard Exchange Server update precautions apply - ensure backups are in place and schedule maintenance window

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Exchange Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-47631 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-47631 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data