CVE-2026-56195 365 apps vulnerability
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
Quick answer
microsoft 365 apps should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- -
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally. This affects Microsoft 365 Apps or Microsoft Office and usually depends on a user opening a crafted document or file. Even information disclosure issues can expose sensitive files, so patch and reduce risky document handling. Use Microsoft 365 update channels, Click-to-Run, or enterprise deployment tools to bring Office to a fixed build.
- Identify users and devices running Microsoft 365 Apps or supported Office builds affected by CVE-2026-56195.
- Install the latest Microsoft Office security update through your managed update channel.
- Block or quarantine unexpected Office files from email, chat, and public upload paths.
- Keep Protected View, macro blocking, and attachment scanning enabled.
- Warn users not to open unknown Word, OneNote, or Office documents until patching is complete.
- Review email security and endpoint logs for suspicious Office file activity.
- If a hostile file was opened, isolate the device and preserve evidence.
Scan now. Google sign-in is only needed to unlock fix guidance.
Verify the fix
- Confirm the Office build number is updated on every affected device.
- Check that no device in scope for CVE-2026-56195 remains on an old Office build without approval.
- Open a known safe document and confirm Office works after the update.
- Review Defender, email gateway, and EDR logs for blocked or opened suspicious documents.
- Record patched device counts and remaining exceptions.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-56195?
microsoft 365 apps versions listed as affected should be reviewed: -.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.