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Microsoft Office Type Confusion Remote Code Execution Vulnerability

IdentifiersCVE-2025-62554CWE-843· Access of Resource Using…

CVE-2025-62554 is a Microsoft Office remote code execution vulnerability caused by access of a resource using an incompatible type (type confusion). The available reporting consistently describes the flaw as affecting Microsoft Office processing of malicious external input, including malicious links and crafted email content. Multiple sources state that Outlook's Preview Pane is an attack vector, meaning specially crafted email content may trigger exploitation during rendering without the victim explicitly opening the attachment or document. Microsoft describes the outcome as local code execution in the context of the affected user.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows arbitrary code execution on the affected system in the security context of the logged-on user. Depending on that user's privileges, an attacker could install programs, modify or delete data, disrupt services, and potentially pivot further into the environment. In high-privilege user contexts, this could result in effective full compromise of the endpoint.

Mitigation

If you can’t patch tonight, do this now.

Until patches are fully deployed, reduce exposure by hardening email workflows and limiting automatic rendering paths associated with Outlook Preview Pane exposure. Treat unsolicited emails, links, and Office content as untrusted; use Protected View / application control where available; restrict execution from user-writable locations; and enforce least privilege so code execution occurs with minimal rights. Additional temporary mitigations specific to this CVE are not clearly documented in the provided content.

Remediation

Patch, then assume compromise.

Apply Microsoft's December 2025 security updates for affected Microsoft Office products and channels. Reported affected offerings include Microsoft 365 Apps for Enterprise, Office 2016, Office 2019, Office LTSC 2021, Office LTSC 2024, Office for Android, and Office LTSC for Mac 2021/2024, with some Mac update information reportedly pending at the time of reporting. Use the Microsoft Security Response Center advisory for CVE-2025-62554 and the relevant Office release notes/update articles to identify and deploy the correct fixed build.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Microsoft Corporation365 Appsapplication
Microsoft Corporation365 Copilotapplication
Microsoft CorporationOfficeapplication
Microsoft CorporationOffice 2016application
Microsoft CorporationOffice 2019application
Microsoft CorporationOffice 2021application
Microsoft CorporationOffice 2024application
Microsoft CorporationOffice Long Term Servicing Channelapplication
Microsoft CorporationOffice Macos 2021application
Microsoft CorporationOffice Macos 2024application

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity6

Community discussion across Reddit, Mastodon, and other social sources.