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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 3 May 2022. Known ransomware use
Exchange ServerApplication · Microsoft

CVE-2020-0688

HIGH · 8.8 CVSS v3.1 Published 2020-02-11
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware High EPSS Public exploit Remotely reachable Zero-click Patch available

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
A remote code execution vulnerability exists in Microsoft Exchange software when the software fails to properly handle objects in memory, aka 'Microsoft Exchange Memory Corruption Vulnerability'.

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

A memory corruption vulnerability in Microsoft Exchange Server allows remote attackers to execute arbitrary code by sending specially crafted requests. The flaw occurs due to improper memory handling when processing objects, enabling authenticated attackers with low privileges to achieve remote code execution without user interaction.

MitigationApply the cumulative security updates released by Microsoft for Exchange Server (KB4536989 and subsequent patches). Implement network segmentation and least-privilege access controls to limit exposure.

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:= 2010= 2013= 2016= 2019

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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. Confirm Exchange Server is installed
    Run 'Get-ExchangeServer | Select-Object Name,Server,IsE14OrLater' in Exchange Management Shell, or check for the 'Microsoft Exchange Active Directory Topology' service
    Affected if No Exchange Server is found, the system is not affected by this CVE
  2. Retrieve the exact Exchange version and build number
    Run 'Get-ExchangeServer | Format-List Name,AdminDisplayVersion' in Exchange Management Shell, or check the registry key 'HKLM\SOFTWARE\Microsoft\ExchangeServer\v15\Setup' for 'Version' and 'BuildNumber'
    Affected if Unable to determine the Exchange version - further manual investigation required
  3. Compare the installed version against affected ranges
    The affected products are Exchange Server 2010, 2013, 2016, and 2019 (all versions within each release). Verify the year portion of the version matches 2010, 2013, 2016, or 2019
    Affected if The installed Exchange version is NOT 2010, 2013, 2016, or 2019 - the system may not be affected (but should still verify the specific build number)
  4. Verify the build is unpatched
    Check the specific build number against Microsoft security bulletin for CVE-2020-0688. Vulnerable builds include: Exchange 2010 (all builds before fix), Exchange 2013 (builds before CU23), Exchange 2016 (builds before CU23), Exchange 2019 (builds before CU10)
    Affected if The Exchange build number matches an unpatched version - the system IS affected by CVE-2020-0688

The system is affected if Microsoft Exchange Server 2010, 2013, 2016, or 2019 is installed without the CVE-2020-0688 security update applied.

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
Patch available Apply the vendor patch
Vendor patch portal.msrc.microsoft.com →
Interim mitigation

Apply the cumulative security updates released by Microsoft for Exchange Server (KB4536989 and subsequent patches). Implement network segmentation and least-privilege access controls to limit exposure.

Recommended fix Moderate confidence

Apply the relevant Cumulative Update + Security Update for your Exchange version (2010 SP3 RU31, 2013 CU23, 2016 CU19/CU20, 2019 CU8/CU9 or later)

  1. Check your current Exchange Server version by running: Get-ExchangeServer | Format-List Name,Edition,Version
  2. Identify the specific Cumulative Update (CU) or Security Update (SU) required for your Exchange version from Microsoft's official documentation
  3. Apply the relevant security update. For Exchange 2010, this requires the Exchange 2010 SP3 RU31; for Exchange 2013, apply CU23 + SU; for Exchange 2016, apply CU19/CU20 + SU; for Exchange 2019, apply CU8/CU9 + SU
  4. After applying the update, verify the installation was successful
  5. Test that Exchange services are functioning properly post-update
  6. Monitor Microsoft Security Response Center for any additional guidance
Caveat Test updates in a non-production environment first; Exchange updates can affect mail flow, OAB generation, and third-party integrations

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

Fix this in Exchange Server Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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-2020-0688 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