CVE-2026-21530: Windows Rich Text Edit Elevation of Privilege Vulnerability
This Microsoft advisory covers CVE-2026-21530 in Windows Server 2012 (Server Core installation), Windows Server 2012 R2 (Server Core installation) and Windows Server 2016 (Server Core installation).
- CVE-2026-21530
Key facts
- Vendor rating
- Medium, CVSS 6.7
- CISA KEV
- Not listed (catalogue checked )
- Affected
- Microsoft 365 Apps for Enterprise 16.0.1 before https://aka.ms/OfficeSecurityReleases; Microsoft Office 2016 16.0.0 before 16.0.5556.1000; Microsoft Office 2019 19.0.0 before https://aka.ms/OfficeSecurityReleases and 9 more below
- Fixed in
- https://aka.ms/OfficeSecurityReleases, 16.0.5556.1000, 10.0.14393.9140 and 9 more below
- Source published
- Source revised
- Listed by VulniPulse
Compiled by VulniPulse from the linked sources. How records are collected and checked.
Affected products & platforms
Description
Double free in Windows Rich Text Edit allows an authorized attacker to elevate privileges locally.
Affected products named by the advisory: Windows Server 2012; Windows Server 2012 (Server Core installation); Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); and 8 more.
Affected products named by the advisory: Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
Text from the source record.
- Microsoft 365 Apps for Enterprise 16.0.1 before https://aka.ms/OfficeSecurityReleases
- Microsoft Office 2016 16.0.0 before 16.0.5556.1000
- Microsoft Office 2019 19.0.0 before https://aka.ms/OfficeSecurityReleases
- Microsoft Office LTSC 2021 16.0.1 before https://aka.ms/OfficeSecurityReleases
- Microsoft Office LTSC 2024 16.0.0 before https://aka.ms/OfficeSecurityReleases
- Windows 10 Version 1607 10.0.14393.0 before 10.0.14393.9140
- Windows 10 Version 1809 10.0.17763.0 before 10.0.17763.8755
- Windows 10 Version 21H2 10.0.19044.0 before 10.0.19044.7291
- Windows 10 Version 22H2 10.0.19045.0 before 10.0.19045.7417
- Windows 11 version 23H2 10.0.22631.0 before 10.0.22631.7079
- Windows 11 Version 23H2 10.0.22631.0 before 10.0.22631.7219
- Windows 11 Version 24H2 10.0.26100.0 before 10.0.26100.8457
Official advisory · high-confidence parse· fetched ·verify at source
How to fix CVE-2026-21530
Upgrade to a fixed release named by Microsoft:
- https://aka.ms/OfficeSecurityReleases
- 16.0.5556.1000
- 10.0.14393.9140
- 10.0.17763.8755
- 10.0.19044.7291
- 10.0.19045.7417
- 10.0.22631.7079
- 10.0.22631.7219
- 10.0.26100.8457
- 10.0.26200.8457
- 10.0.28000.2113
- 6.2.9200.26079
End-of-life dates for Windows Server
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