CVE-2026-102858 Microsoft Office OneNote Remote Code Execution Vulnerability
Heap-based buffer overflow in Microsoft Office OneNote allows remote attackers to execute arbitrary code over the network.
- 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-2026-102858?
CVE-2026-102858 is a high-severity memory corruption vulnerability in Microsoft Microsoft 365, published on 13 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
Heap-based buffer overflow in Microsoft Office OneNote allows an unauthorized attacker to execute code over a network.
Weakness: CWE-122
Which versions are affected by CVE-2026-102858?
It affects 3 products.
Products include Microsoft Microsoft 365, Microsoft Office 2021, Microsoft Office 2024.
How do I fix CVE-2026-102858?
No fix has been published for CVE-2026-102858 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-2026-102858 being exploited?
There is no known exploitation of CVE-2026-102858 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Microsoft 365
Sources
Also known as GHSA-r6w3-7r2g-5962.