Double Free in Microsoft 365 Apps For Enterprise
CVE-2026-21530
Double free in Windows Rich Text Edit allows an authorized attacker to elevate privileges locally.
Vulnerability class: Double Free
EPSS: 0.003 (24.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Microsoft 365 Apps For Enterprise — versions 16.0.1
- Microsoft Office 2016 — versions 16.0.0
- Microsoft Office 2019 — versions 19.0.0
- Microsoft Office Ltsc 2021 — versions 16.0.1
- Microsoft Office Ltsc 2024 — versions 16.0.0
- Microsoft Windows_10_1607
- Microsoft Windows_10_1809
- Microsoft Windows_10_21h2
- Microsoft Windows_10_22h2
- Microsoft Windows 10 Version 1607 — versions 10.0.14393.0
Weakness classification (CWE)
References
- secure@microsoft.com (vendor-advisory, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-21530?
- CVE-2026-21530 is a medium-severity vulnerability in Microsoft 365 Apps For Enterprise, classified under Double Free. CVSS score: 6.7/10. Published 2026-05-12.
- How severe is CVE-2026-21530?
- Medium severity. CVSS v3 base score is 6.7 out of 10.