CVE-2025-62216: Microsoft 365 Apps Use After Free Flaw

CVE-2025-62216 Overview

CVE-2025-62216 is a use-after-free vulnerability [CWE-416] in Microsoft Office that enables local code execution. An attacker can craft a malicious Office document that, when opened by a user, triggers memory corruption and runs arbitrary code in the context of the current user. The flaw affects Microsoft 365 Apps and Microsoft Office Long Term Servicing Channel (LTSC) 2021 and 2024 across x86 and x64 architectures. Exploitation requires user interaction but no prior authentication. Microsoft published the advisory on November 11, 2025.

Critical Impact

Successful exploitation allows arbitrary local code execution with the privileges of the targeted user, leading to full compromise of confidentiality, integrity, and availability on the affected host.

Affected Products

• Microsoft 365 Apps (Enterprise, x86 and x64)
• Microsoft Office LTSC 2021 (x86 and x64)
• Microsoft Office LTSC 2024 (x86 and x64)

Discovery Timeline

• 2025-11-11 - CVE-2025-62216 published to NVD and Microsoft Security Response Center advisory released
• 2025-11-17 - Last updated in NVD database

Technical Details for CVE-2025-62216

Vulnerability Analysis

The vulnerability is a use-after-free condition within Microsoft Office. Office code releases a heap object but retains and later dereferences a pointer to that freed memory. When the attacker controls the contents of the reclaimed allocation, the dangling reference is dereferenced as if it were the original object. This allows the attacker to redirect execution flow into attacker-controlled data.

The attack vector is local and requires the victim to open a crafted Office document. The vulnerability does not require elevated privileges to trigger. Code executes with the same rights as the user running Office, which on most workstations is a standard interactive user but may include administrative tokens on developer or admin endpoints.

Root Cause

The root cause is improper object lifetime management in Office document parsing routines. A reference to a heap-allocated object is used after the object has been freed. Microsoft has not published implementation-level details. Refer to the Microsoft Security Advisory for vendor guidance.

Attack Vector

An attacker delivers a weaponized document through phishing email, a malicious file share, a removable drive, or a drive-by download. The user must open the file in a vulnerable version of Office. Preview Pane interaction may also be sufficient for some Office file formats. Once the use-after-free triggers, the attacker can chain it with heap grooming and leak primitives to achieve reliable arbitrary code execution.

No public proof-of-concept exploit is currently available, and the vulnerability is not listed on the CISA Known Exploited Vulnerabilities catalog at the time of writing.

Detection Methods for CVE-2025-62216

Indicators of Compromise

• Office processes (WINWORD.EXE, EXCEL.EXE, POWERPNT.EXE) spawning unexpected child processes such as cmd.exe, powershell.exe, rundll32.exe, or mshta.exe
• Office applications writing executable content (.exe, .dll, .scr) to user-writable paths like %TEMP%, %APPDATA%, or %PUBLIC%
• Crash events in the Application event log naming an Office binary with access violation faulting modules
• Outbound network connections initiated directly by an Office process to uncategorized or newly registered domains

Detection Strategies

• Monitor parent-child process relationships where Office binaries spawn scripting or LOLBin processes
• Hunt for in-memory injection patterns originating from Office process address space, including VirtualAlloc followed by CreateRemoteThread
• Inspect inbound email attachments for malformed Office file structures using sandbox detonation
• Correlate document open events with subsequent file write and network activity within a short time window

Monitoring Recommendations

• Enable and forward Microsoft Defender Attack Surface Reduction (ASR) audit and block events to a central log store
• Stream Sysmon event IDs 1, 7, 10, and 11 from endpoints running Office
• Track Office crash telemetry via Windows Error Reporting to surface exploitation attempts that fail mid-chain
• Alert on Office macro execution events from documents originating outside the corporate trust zone

How to Mitigate CVE-2025-62216

Immediate Actions Required

• Apply the November 2025 Microsoft security updates for Microsoft 365 Apps and Office LTSC 2021 and 2024 from the Microsoft Security Advisory
• Confirm Click-to-Run Office installations are receiving updates and force update channels where deployment has lagged
• Block inbound Office documents from untrusted external senders at the email gateway until patching is verified
• Enable Microsoft Defender ASR rules that block Office applications from creating child processes and executable content

Patch Information

Microsoft released fixes through the November 2025 Patch Tuesday cycle. Administrators should consult the Microsoft Security Advisory for the specific build numbers that remediate CVE-2025-62216 in each affected channel and architecture.

Workarounds

• Open untrusted documents only in Protected View and prevent users from disabling it via Group Policy
• Disable the Outlook Preview Pane to reduce automatic rendering of attached Office files
• Restrict Office macro execution to digitally signed macros from trusted publishers
• Run Office under standard user accounts to limit the impact of successful exploitation

# Example: enforce ASR rule to block Office child process creation
Set-MpPreference -AttackSurfaceReductionRules_Ids `
  D4F940AB-401B-4EFC-AADC-AD5F3C50688A `
  -AttackSurfaceReductionRules_Actions Enabled