CVE-2026-40421 Microsoft Word Information Disclosure Vulnerability
An unauthorized attacker can disclose local information via accessible files or directories in Microsoft Word, requiring a patch.
- 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-2026-40421?
CVE-2026-40421 is a medium-severity vulnerability in Microsoft 365 Apps, published on 12 May 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
Files or directories accessible to external parties in Microsoft Office Word allows an unauthorized attacker to disclose information locally.
Weakness: CWE-73
Which versions are affected by CVE-2026-40421?
It affects 4 products.
Products include Microsoft 365 Apps, Microsoft Office, Microsoft Office Long Term Servicing Channel, Microsoft Word.
How do I fix CVE-2026-40421?
No fix has been published for CVE-2026-40421 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-40421 being exploited?
There is no known exploitation of CVE-2026-40421 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-m493-43x7-h3mj.