CVE-2026-78509: Microsoft Office Outlook Remote Code Execution Vulnerability
Heap-based buffer overflow in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
Other sources
Microsoft Office Outlook Remote Code Execution Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.14334.20896 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.17932.20960 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.5569.1000Patch KB5002923 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.10417.20204 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.20326.20136
Event History
Frequently Asked Questions
Which Office deployments are identified as affected?
The listed affected software includes Microsoft Word 2016, Microsoft 365 Apps for Enterprise, Office 2019 for 64-bit editions, Office LTSC 2021 for 32-bit editions, Office LTSC 2024 for 32-bit and 64-bit editions, and Office LTSC for Mac 2021 and 2024.
Does exploitation require an authenticated account or user interaction?
No. The supplied severity vector indicates network attack access, low attack complexity, no privileges required, and no user interaction required.
What is the potential impact of successful exploitation?
An unauthorized attacker could execute code remotely. The severity vector indicates high impact to confidentiality, integrity, and availability.