CVE-2026-108446 Microsoft Office Excel Remote Code Execution Vulnerability
An attacker can execute arbitrary code remotely by exploiting a use-after-free flaw in Microsoft Office Excel.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-108446?
CVE-2026-108446 is a high-severity use after free vulnerability in Microsoft 365 Apps, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.
Weakness: CWE-416
Which versions are affected by CVE-2026-108446?
It affects 5 products.
Products include Microsoft 365 Apps, Microsoft Microsoft 365, Microsoft Office 2021, Microsoft Office 2024, Microsoft Office Online Server.
How do I fix CVE-2026-108446?
No fix has been published for CVE-2026-108446 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-2026-108446 being exploited?
There is no known exploitation of CVE-2026-108446 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-q438-8jwr-4rqf.