CVE-2026-45456 Microsoft Outlook and Word Remote Code Execution Vulnerability
An attacker can execute arbitrary code locally via type confusion in Microsoft Office applications, requiring user interaction to open a malicious file.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-45456?
CVE-2026-45456 is a high-severity memory corruption vulnerability in Microsoft 365 Apps, published on 9 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Access of resource using incompatible type ('type confusion') in Microsoft Office allows an unauthorized attacker to execute code locally.
Weakness: CWE-843
Which versions are affected by CVE-2026-45456?
It affects 7 products.
Products include Microsoft 365 Apps, Microsoft Microsoft 365, Microsoft Office 2016, Microsoft Office 2019, Microsoft Office 2021, Microsoft Office 2024 and 1 more.
How do I fix CVE-2026-45456?
No fix has been published for CVE-2026-45456 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-45456 being exploited?
There is no known exploitation of CVE-2026-45456 in the wild and no public exploit code.
Other vulnerabilities in Microsoft 365 Apps
- CVE-2024-21413 Microsoft Outlook Improper Input Validation
- CVE-2023-23397 Microsoft Office Outlook Privilege Escalation
- CVE-2024-38189 Microsoft Project Remote Code Execution Vulnerability
- CVE-2023-35311 Microsoft Outlook Security Feature Bypass
- CVE-2026-21514 Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision
Sources
Also known as GHSA-6gjp-59mg-98gh.