CVE record · CVE-2021-26887

Microsoft Windows Folder Redirection Elevation of Privilege Vulnerability

CVSS 7.8 HighEPSS 0.011 · 64th percentile

Published by the CVE Program (CNA: microsoft) at 11 Mar 2021, 15:42 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
Microsoft	Windows 10 Version 1507	affected -
Microsoft	Windows 10 Version 1607	affected -
Microsoft	Windows 10 Version 1803	affected -
Microsoft	Windows 10 Version 1809	affected -
Microsoft	Windows 10 Version 1809	affected -
Microsoft	Windows 10 Version 1909	affected -
Microsoft	Windows 10 Version 2004	affected -
Microsoft	Windows 10 Version 20H2	affected -
Microsoft	Windows 7	affected -
Microsoft	Windows 7 Service Pack 1	affected -
Microsoft	Windows 8.1	affected -
Microsoft	Windows Server 2008 R2 Service Pack 1	affected -
Microsoft	Windows Server 2008 R2 Service Pack 1 (Server Core installation)	affected -
Microsoft	Windows Server 2008 Service Pack 2	affected -
Microsoft	Windows Server 2008 Service Pack 2 (Server Core installation)	affected -
Microsoft	Windows Server 2012	affected 6.2.9200.0 to before 6.2.9200.23298 custom
Microsoft	Windows Server 2012 (Server Core installation)	affected 6.2.9200.0 to before 6.2.9200.23298 custom
Microsoft	Windows Server 2012 R2	affected -
Microsoft	Windows Server 2012 R2 (Server Core installation)	affected -
Microsoft	Windows Server 2016	affected -
Microsoft	Windows Server 2016 (Server Core installation)	affected -
Microsoft	Windows Server 2019	affected -
Microsoft	Windows Server 2019 (Server Core installation)	affected -
Microsoft	Windows Server version 2004	affected -
Microsoft	Windows Server version 20H2	affected -
Microsoft	Windows Server, version 1909 (Server Core installation)	affected -

Identifiers: CVE-2021-26887
CNA: microsoft
Tags: Microsoft Windows 10 Version 1507
Microsoft Windows 10 Version 1607
Microsoft Windows 10 Version 1803
Microsoft Windows 10 Version 1809
Microsoft Windows 10 Version 1909
Microsoft Windows 10 Version 2004
Microsoft Windows 10 Version 20H2
Microsoft Windows 7
Published: 11 Mar 2021
Updated: 19 Aug 2026

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.8	High	3.1	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C	CNA (microsoft)

CISA KEV Not listed.
EPSS 0.011, the 64th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 11 Mar 2021. New records show when each source confirmed them.

Sources

References from the CNA

msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26887 vendor-advisorypatch

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.