Medium severity · published May 12, 2026
CVE-2026-21530
Windows Rich Text Edit Elevation of Privilege Vulnerability
6.7
CVSS
0.3%
EPSS
No
On KEV
Description
Double free in Windows Rich Text Edit allows an authorized attacker to elevate privileges locally.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
M3
Microsoft 365 Apps for Enterprise · Microsoft
16.0.1 before https://aka.ms/OfficeSecurityReleases · source: vendor
MO
Microsoft Office 2016 · Microsoft
16.0.0 before 16.0.5556.1000 · source: vendor
MO
Microsoft Office 2019 · Microsoft
19.0.0 before https://aka.ms/OfficeSecurityReleases · source: vendor
MO
Microsoft Office LTSC 2021 · Microsoft
16.0.1 before https://aka.ms/OfficeSecurityReleases · source: vendor
MO
Microsoft Office LTSC 2024 · Microsoft
16.0.0 before https://aka.ms/OfficeSecurityReleases · source: vendor
W1
Windows 10 Version 1607 · Microsoft
10.0.14393.0 before 10.0.14393.9140 · source: vendor
W1
Windows 10 Version 1809 · Microsoft
10.0.17763.0 before 10.0.17763.8755 · source: vendor
W1
Windows 10 Version 21H2 · Microsoft
10.0.19044.0 before 10.0.19044.7291 · source: vendor
W1
Windows 10 Version 22H2 · Microsoft
10.0.19045.0 before 10.0.19045.7417 · source: vendor
W1
Windows 11 Version 24H2 · Microsoft
10.0.26100.0 before 10.0.26100.8457 · source: vendor
W1
Windows 11 Version 25H2 · Microsoft
10.0.26200.0 before 10.0.26200.8457 · source: vendor
W1
Windows 11 version 23H2 · Microsoft
10.0.22631.0 before 10.0.22631.7079; 10.0.22631.0 before 10.0.22631.7219 · source: vendor
Affected product
M3
Microsoft 365 Apps for Enterprise
Microsoft
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21530
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-21530
Vendor Advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21530
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