No exploitation reportedFix available

CVE-2020-1023

No exploitation reported by the sources we read.

Published2020-05-21
WeaknessCWE-434

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A remote code execution vulnerability exists in Microsoft SharePoint when the software fails to check the source markup of an application package. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the SharePoint application pool and the SharePoint server farm account. Exploitation of this vulnerability requires that a user uploads a specially crafted SharePoint application package to an affected version of SharePoint. The security update addresses the vulnerability by correcting how SharePoint checks the source markup of application packages.

Timeline

dates in UTC

2020-05-2123:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-1023?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-1023?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Microsoft sharepoint enterprise server

Branch	Affected	Fixed in	Source
2016.x	= 2016	no fix published	NVD

Microsoft sharepoint foundation

Branch	Affected	Fixed in	Source
2013.x	= 2013	no fix published	NVD

Microsoft sharepoint server

Branch	Affected	Fixed in	Source
2019.x	= 2019	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

portal.msrc.microsoft.comPatch · Vendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.18.8read 2026-10-23
NVDCVSS 2.06.5read 2026-10-23
NVDweakness (CWE)CWE-434read 2026-10-23
FIRST EPSSEPSS score3.7 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published: 2020-05-21
Last Modified: 2026-08-19
NVD status: Modified

Frequently asked questions

What is CVE-2020-1023?

Is CVE-2020-1023 actively exploited?

Active exploitation of CVE-2020-1023 has not been confirmed. Its EPSS score was 3.7% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-1023?

CVE-2020-1023 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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