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CVE-2020-0688

Microsoft Exchange Server Validation Key Remote Code Execution

8.8 HIGHActively exploited (CISA KEV)Used in ransomwarePublic exploitEPSS 100.0%
  1. Published11 Feb 2020
  2. Added to CISA KEV3 Nov 2021
  3. Remediation due3 May 2022
Actively exploited (CISA KEV)

Microsoft Exchange Server Validation Key fails to properly create unique keys at install time, allowing for remote code execution.

Added to KEV: 3 Nov 2021Federal remediation due: 3 May 2022Used in ransomware

Description

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'.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft Exchange Server2010 · 2013 · 2016 · 2019

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2020-0688 being actively exploited?

Yes. CVE-2020-0688 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021. It has been used in ransomware campaigns.

How severe is CVE-2020-0688?

CVE-2020-0688 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 100.0% probability of exploitation.

Which products are affected by CVE-2020-0688?

Affected products include Microsoft Exchange Server.

How do I fix CVE-2020-0688?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2020-0688 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.