CVE-2026-45458 Microsoft Outlook and Word Remote Code Execution Vulnerability
An attacker can execute arbitrary code locally via a use-after-free vulnerability in Microsoft Office applications.
- 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-2026-45458?
CVE-2026-45458 is a high-severity use after free 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
Use after free in Microsoft Office allows an unauthorized attacker to execute code locally.
Weakness: CWE-416
Which versions are affected by CVE-2026-45458?
It affects 7 products.
Products include Microsoft 365 Apps, Microsoft Microsoft 365, Microsoft Office 2019, Microsoft Office 2021, Microsoft Office 2024, Microsoft Sharepoint Server and 1 more.
How do I fix CVE-2026-45458?
No fix has been published for CVE-2026-45458 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-45458 being exploited?
There is no known exploitation of CVE-2026-45458 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-5632-qjr7-ch9q.