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Exchange ServerApplication · Microsoft

CVE-2025-59248

HIGH · 7.5 CVSS v3.1 Published 2025-10-14
Fix available
A fix is available. Upgrade to 15.02.2562.029 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 input validation in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.

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

Improper input validation in Microsoft Exchange Server allows an unauthenticated attacker to spoof valid users or components over the network by sending specially crafted input that the server processes without proper validation.

MitigationApply the Microsoft security patch for Exchange Server when available, and verify input handling configurations align with vendor hardening guidelines.

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:< 15.02.2562.029

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
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 Exchange Server installation
    Run 'Get-ExchangeServer | Format-List Name,AdServers,ServerRole,DistinguishedName,Identity' in Exchange Management Shell or check Programs and Features to confirm Microsoft Exchange Server is installed
    Affected if No Exchange Server is found, the system is not affected by this CVE
  2. Retrieve Exchange Server version
    Run 'Get-ExchangeServer | Format-List Name,AdminDisplayVersion' in Exchange Management Shell, or check the version from Exchange Setup (Setup.exe /IAcceptExchangeServerLicenseTerms /Mode:Install /Role:Mailbox /DomainController:<dc>)
    Affected if Unable to determine the version means the detection step is inconclusive for this CVE
  3. Compare installed version against affected ranges
    Verify if the installed version matches Exchange Server 2016, Exchange Server 2019, or Exchange Server Subscription Edition with build number less than 15.02.2562.029
    Affected if The installed version falls within Exchange 2016, Exchange 2019, or Subscription Edition < 15.02.2562.029, indicating the environment is potentially affected by this input validation flaw

The environment is affected if Microsoft Exchange Server 2016, 2019, or Subscription Edition with build below 15.02.2562.029 is installed and the spoofing vulnerability via improper input validation is present.

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 15.02.2562.029 or later
Fixed in 15.02.2562.029
Interim mitigation

Apply the Microsoft security patch for Exchange Server when available, and verify input handling configurations align with vendor hardening guidelines.

Recommended fix Moderate confidence

Apply the latest Cumulative Update (CU) for Exchange Server 2016 or 2019 that includes the security fix (build 15.02.2562.029 or later for Subscription Edition)

  1. Identify your current Exchange Server version by running 'Get-ExchangeServer | Format-List Name,Edition,AdminDisplayVersion' in Exchange Management Shell
  2. Navigate to the Microsoft Update Catalog or Microsoft Download Center to obtain the latest Cumulative Update for your Exchange Server version (2016 or 2019)
  3. Review the release notes for the latest Cumulative Update to understand any prerequisites and known issues
  4. Backup your Exchange Server environment including mailbox databases and configuration
  5. Install the latest Cumulative Update on your Exchange Server, following Microsoft's standard upgrade procedures
  6. After installation, verify the update was successful by checking the version with 'Get-ExchangeServer | Format-List Name,Edition,AdminDisplayVersion'
  7. Verify that the build number matches or exceeds 15.02.2562.029 for Subscription Edition or the equivalent fixed build for Exchange Server 2016/2019
  8. Test critical Exchange services (OWA, ECP, SMTP, IMAP, POP) to ensure functionality
Caveat Cumulative Updates may include schema changes; review release notes for any configuration adjustments or prerequisites before applying

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

Fix this in Exchange Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

Scan for this in your stack

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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-2025-59248 in production — separate from our analysis above.

No notes yet

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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