CVE-2020-0688: Microsoft Exchange Server Validation Key Remote Code Execution Vulnerability

CVE-2020-0688 · Severity: critical · CVSS 8.8 · Exploited in the wild · Published 2021-11-03

Microsoft Exchange Server fails to properly create unique validation keys at installation time. This vulnerability allows an authenticated remote attacker to execute arbitrary code by sending a specially crafted request to the server, leading to a deserialization flaw.

Technologies: Microsoft Exchange Server. Vendors: Microsoft.

Quick answers

Is CVE-2020-0688 exploited in the wild?
Yes. CVE-2020-0688 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.
How severe is CVE-2020-0688?
Critical severity, with a CVSS score of 8.8, published 3 November 2021.
Which products and versions are affected?
Microsoft Exchange Server 2010 SP3 Rollup 30; Microsoft Exchange Server 2013 Cumulative Update 23; Microsoft Exchange Server 2016 Cumulative Update 14; Microsoft Exchange Server 2016 Cumulative Update 15; and 2 more.
Is there a fix for CVE-2020-0688?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2020-0688 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2020-0688?
Check whether you run Microsoft Exchange Server. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Affected products

  • Microsoft Exchange Server 2010 SP3 Rollup 30
  • Microsoft Exchange Server 2013 Cumulative Update 23
  • Microsoft Exchange Server 2016 Cumulative Update 14
  • Microsoft Exchange Server 2016 Cumulative Update 15
  • Microsoft Exchange Server 2019 Cumulative Update 3
  • Microsoft Exchange Server 2019 Cumulative Update 4

Timeline

  • 2020-02-11: advisory: MSRC advisory published
  • 2020-02-13: other: Initial NIST analysis and CVSS scoring completed
  • 2021-11-03: kev added: Added to CISA Known Exploited Vulnerabilities Catalog

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