CVE-2020-17117Exchange Server Vulnerability
Microsoft Exchange Remote Code Execution Vulnerability
Published Dec 9, 2020 · Updated Jun 9, 2026
Key Facts
Patch in the next maintenance window- CVE-2020-17117 is a high-severity vulnerability (CVSS 7.2 v3.1) affecting Exchange Server (Microsoft), Microsoft Exchange Server 2013 Cumulative Update 23, Microsoft Exchange Server 2016 Cumulative Update 17 and 3 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 49% probability of exploitation in the next 30 days.
- Fixed versions are available, including Microsoft Exchange Server 2013 Cumulative Update 23 publication, Microsoft Exchange Server 2016 Cumulative Update 17 publication, Microsoft Exchange Server 2016 Cumulative Update 18 publication.
- Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
Scores
CVSS v3.1
7.2
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
49%
Higher than 98.8% of all scored CVEs
Exploit maturity
None known
ATLAS score
42/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
None known
Public exploit code
0
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Advisories And Exploit References
- advisoryhttp://redmondmag.1105cms01.com/Articles/List/News.aspx
- advisoryhttps://isc.sans.edu/diary/rss/26860
- advisoryhttps://msrc.microsoft.com/update-guide/releaseNote/2020-Dec
- advisoryhttps://redmondmag.1105cms01.com/articles/2020/12/08/microsoft-december-patch-bundle.aspx
- advisoryhttps://redmondmag.com/articles/2020/11/10/microsoft-november-security-bundle.aspx
- advisoryhttps://us-cert.cisa.gov/ncas/current-activity/2020/12/08/microsoft-releases-december-2020-security-updates
Description
Microsoft Exchange Remote Code Execution Vulnerability
Affected Products
10 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Exchange ServerMicrosoft | 2013-cumulative_update_23, 2016-cumulative_update_17, 2016-cumulative_update_18, 2019-cumulative_update_6, 2019-cumulative_update_7 | n/a |
| Microsoft Exchange Server 2013 Cumulative Update 23 | >= 15.00.0 | publication |
| Microsoft Exchange Server 2016 Cumulative Update 17 | >= 15.01.0 | publication |
| Microsoft Exchange Server 2016 Cumulative Update 18 | >= 15.01.0 | publication |
| Microsoft Exchange Server 2019 Cumulative Update 6 | >= 15.02.0 | publication |
Patched Releases
Microsoft Exchange Server 2013 Cumulative Update 23
publication
Microsoft Exchange Server 2016 Cumulative Update 17
publication
Microsoft Exchange Server 2016 Cumulative Update 18
publication
Microsoft Exchange Server 2019 Cumulative Update 6
publication
Microsoft Exchange Server 2019 Cumulative Update 7
publication
Timeline
Publicly disclosed
Dec 9, 2020
Last updated
Jun 9, 2026
References
- advisoryredmondmag.1105cms01.com · News.aspx
- advisoryisc.sans.edu · 26860
- advisorymsrc.microsoft.com · 2020-Dec
- advisoryredmondmag.1105cms01.com · microsoft-december-patch-bundle.aspx
- advisoryredmondmag.com · microsoft-november-security-bundle.aspx
FAQ
Common Questions.
Microsoft Exchange Remote Code Execution Vulnerability
Affected: Exchange Server (Microsoft) versions 2013-cumulative_update_23, 2016-cumulative_update_17, 2016-cumulative_update_18, 2019-cumulative_update_6, 2019-cumulative_update_7; Microsoft Exchange Server 2013 Cumulative Update 23 versions >= 15.00.0; Microsoft Exchange Server 2016 Cumulative Update 17 versions >= 15.01.0, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Microsoft Exchange Server 2013 Cumulative Update 23 publication, Microsoft Exchange Server 2016 Cumulative Update 17 publication, Microsoft Exchange Server 2016 Cumulative Update 18 publication.
Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
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