Double free in Windows and Windows Server - CVE-2026-21530
Published: May 12, 2026
Vulnerability identifier: #VU131207
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-21530
CWE-ID: CWE-415
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Microsoft
Affected software:
Windows
Windows Server
Windows
Windows Server
Detailed vulnerability description
The vulnerability allows a remote attacker to escalate privileges on the system.
The vulnerability exists due to a boundary error in Windows Rich Text Edit. A remote user can trick a victim to open a specially crafted file, win a race condition and gain elevated elevated privileges on the target system.
How to mitigate CVE-2026-21530
Install updates from vendor's website.