CVE-2025-62557 Overview
CVE-2025-62557 is a use-after-free vulnerability [CWE-416] in Microsoft Office that enables local code execution. An attacker with low privileges can execute arbitrary code on a target system by triggering the flaw through a crafted Office document. The vulnerability affects Microsoft 365 Apps, Microsoft 365 Copilot, Microsoft Office 2016 and 2019, and the Office Long Term Servicing Channel 2021 and 2024 releases across Windows and macOS.
Critical Impact
Successful exploitation grants an attacker full confidentiality, integrity, and availability impact on the affected host, enabling code execution in the context of the current user.
Affected Products
- Microsoft 365 Apps (Enterprise, x64 and x86)
- Microsoft 365 Copilot (Android)
- Microsoft Office 2016 and 2019 (x64 and x86)
- Microsoft Office Long Term Servicing Channel 2021 and 2024 (Windows and macOS)
Discovery Timeline
- 2025-12-09 - CVE-2025-62557 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-62557
Vulnerability Analysis
CVE-2025-62557 is a use-after-free memory corruption issue in Microsoft Office. The flaw occurs when Office code references a memory region after that region has already been freed. An attacker who controls the contents of the reallocated memory can steer execution flow, ultimately achieving arbitrary code execution in the Office process.
Exploitation requires local access and low privileges, but no user interaction beyond opening a crafted document is required per the CVSS vector. The attack surface spans the desktop Office suite and Microsoft 365 Apps, meaning the vulnerability applies broadly across enterprise Office deployments.
Root Cause
The root cause is improper object lifetime management within an Office component. When the vulnerable code path frees an object but retains a dangling pointer, subsequent operations dereference that stale pointer. Attackers can groom the heap to place attacker-controlled data at the freed location, converting the dangling reference into a controlled read or write primitive.
Attack Vector
The attack vector is local. A typical exploitation scenario involves delivering a maliciously crafted Office document (Word, Excel, or PowerPoint) via email, file share, or web download. When the target opens the document, the parsing logic triggers the use-after-free condition. Code execution occurs in the security context of the user running Office, which can be leveraged for further lateral movement or privilege escalation.
No public proof-of-concept or in-the-wild exploitation has been reported at time of publication. Refer to the Microsoft Security Update Guide for CVE-2025-62557 for vendor-supplied technical details.
Detection Methods for CVE-2025-62557
Indicators of Compromise
- Office applications (WINWORD.EXE, EXCEL.EXE, POWERPNT.EXE) spawning unexpected child processes such as cmd.exe, powershell.exe, wscript.exe, or rundll32.exe.
- Unexpected outbound network connections initiated by Office processes shortly after a document is opened.
- Office process crashes with access violation exceptions correlated to opening a specific document.
- Newly created executables, scripts, or scheduled tasks under user profile directories following document interaction.
Detection Strategies
- Deploy behavioral endpoint detection rules that flag Office applications loading unusual DLLs or performing process hollowing.
- Correlate Microsoft Defender or Windows Event Log entries showing Office application faults with subsequent process creation events.
- Inspect inbound email attachments and file shares for Office documents containing embedded objects, unusual OLE streams, or malformed structures.
Monitoring Recommendations
- Enable Sysmon Event IDs 1 (process creation) and 3 (network connection) with a rule set that scopes Office parent processes.
- Forward Office telemetry to a centralized SIEM or data lake for cross-host correlation and threat hunting.
- Track patch deployment status across all Office installations using endpoint management tooling to identify unpatched hosts.
How to Mitigate CVE-2025-62557
Immediate Actions Required
- Apply the Microsoft security update for CVE-2025-62557 across all affected Office installations without delay.
- Prioritize patching for users who routinely handle external documents such as executives, finance, HR, and support staff.
- Verify Microsoft 365 Apps update channels are configured to receive current security releases automatically.
Patch Information
Microsoft has released security updates addressing CVE-2025-62557. Refer to the Microsoft Security Update Guide for CVE-2025-62557 for build numbers and per-product patch downloads. Ensure both Windows and macOS Office installations are updated, as the Long Term Servicing Channel builds affect both platforms.
Workarounds
- Enable Protected View for documents originating from the internet, email attachments, and unsafe locations.
- Enforce Office Attack Surface Reduction (ASR) rules that block Office applications from creating child processes.
- Use Group Policy to disable execution of macros and ActiveX controls in documents from untrusted sources until patches are deployed.
- Restrict end-user privileges so exploitation cannot easily be chained to broader system compromise.
# Configuration example: Enable ASR rule to block Office child process creation
Set-MpPreference -AttackSurfaceReductionRules_Ids D4F940AB-401B-4EFC-AADC-AD5F3C50688A -AttackSurfaceReductionRules_Actions Enabled
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
