CVE-2026-77504 Microsoft Office Word Remote Code Execution Vulnerability
An attacker can execute arbitrary code remotely by exploiting a double free vulnerability in Microsoft Office Word.
- 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-2026-77504?
CVE-2026-77504 is a high-severity use after free vulnerability in Microsoft Windows 10 1607, published on 8 Sep 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
Double free in Microsoft Office Word allows an unauthorized attacker to execute code over a network.
Weakness: CWE-415
Which versions are affected by CVE-2026-77504?
It affects 13 products.
Products include Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 23h2, Microsoft Windows 11 24h2 and 7 more.
How do I fix CVE-2026-77504?
No fix has been published for CVE-2026-77504 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-2026-77504 being exploited?
There is no known exploitation of CVE-2026-77504 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows 10 1607
- CVE-2026-33824 Microsoft Internet Key Exchange (IKE) Service Extensions Double Free
- CVE-2026-21510 Microsoft Windows Shell Protection Mechanism Failure
- CVE-2026-21513 Microsoft MSHTML Framework Protection Mechanism Failure
- CVE-2023-32049 Microsoft Windows Defender SmartScreen Security Feature Bypass
- CVE-2023-29360 Microsoft Streaming Service Untrusted Pointer Dereference
Sources
Also known as GHSA-mpf5-fg2g-h5xp.