CVE-2026-88156 Microsoft Office Outlook Remote Code Execution Vulnerability
An unauthorized attacker can execute arbitrary code remotely via a stack-based buffer overflow in Microsoft Office Outlook.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-88156?
CVE-2026-88156 is a critical memory corruption vulnerability in Microsoft 365 Apps, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Stack-based buffer overflow in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
Weakness: CWE-121
Which versions are affected by CVE-2026-88156?
It affects 4 products.
Products include Microsoft 365 Apps, Microsoft Microsoft 365, Microsoft Office 2021, Microsoft Office 2024.
How do I fix CVE-2026-88156?
No fix has been published for CVE-2026-88156 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-2026-88156 being exploited?
There is no known exploitation of CVE-2026-88156 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-pxgg-c4xh-w6pg.