CVE-2024-49031: Microsoft 365 Apps RCE Vulnerability

CVE-2024-49031 Overview

CVE-2024-49031 is a remote code execution vulnerability in the Microsoft Office graphics component. The flaw affects Microsoft 365 Apps, Microsoft Office 2016, Microsoft Office 2019, and the Microsoft Office Long Term Servicing Channel (LTSC) 2021 and 2024 releases, including macOS builds. Microsoft classifies the issue under [CWE-126] (Buffer Over-read) in the graphics parsing logic. Successful exploitation allows an attacker to execute code in the context of the current user after that user opens a crafted Office document.

Critical Impact
An attacker who successfully exploits CVE-2024-49031 can execute arbitrary code locally with the privileges of the user opening the malicious file, resulting in high impact to confidentiality, integrity, and availability.

Affected Products

Microsoft 365 Apps (Enterprise)
Microsoft Office 2016 and Microsoft Office 2019
Microsoft Office LTSC 2021 and Microsoft Office LTSC 2024 (Windows and macOS)

Discovery Timeline

2024-11-12 - CVE-2024-49031 published to the National Vulnerability Database (NVD)
2024-11-12 - Microsoft released the security update addressing CVE-2024-49031
2026-06-17 - Last updated in the NVD database

Technical Details for CVE-2024-49031

Vulnerability Analysis

CVE-2024-49031 resides in the Microsoft Office graphics component responsible for parsing embedded image and drawing data inside Office documents. The CWE-126 classification identifies a buffer over-read, in which the parser reads past the end of an allocated buffer while processing malformed graphics structures. This out-of-bounds read can be combined with attacker-controlled memory layout to leak state or corrupt program flow, enabling arbitrary code execution in the Office process. The attack vector is local: the target must open a specifically crafted document or preview it in an application that renders the Office graphics stack. Because Office runs with the interactive user's token, code executes at that privilege level and can be used for follow-on activity such as credential theft, lateral movement, or loader staging.

Root Cause

The root cause is improper validation of graphics object metadata before the parser reads structured fields from the document. When length or offset values inside the file exceed the allocated buffer, the parser accesses memory outside the intended region. The condition maps to [CWE-126] and reflects missing bounds checks in the Office graphics rendering path.

Attack Vector

Exploitation requires user interaction and local access. An attacker typically delivers a weaponized .docx, .xlsx, .pptx, or related Office format through phishing email, malicious SharePoint or OneDrive links, or removable media. When the user opens the file, the vulnerable graphics parser processes the malicious object and triggers the memory access flaw. No network authentication is required, and privileges match the current user session. Microsoft has not published proof-of-concept code, and no public exploit is available at the time of writing. See the Microsoft Security Update Guide for CVE-2024-49031 for vendor-specific technical detail.

Detection Methods for CVE-2024-49031

Indicators of Compromise

Office documents containing malformed embedded graphics, drawings, or OLE objects that trigger crashes in winword.exe, excel.exe, or powerpnt.exe
Unexpected child processes such as cmd.exe, powershell.exe, wscript.exe, or rundll32.exe spawned from an Office application
Windows Error Reporting (WER) crash artifacts referencing the Office graphics filter modules following the opening of an emailed document

Detection Strategies

Alert on Office applications spawning script interpreters or LOLBins immediately after document open events
Hunt for Office processes writing executables or DLLs to %APPDATA%, %TEMP%, or %PUBLIC% and subsequently loading them
Correlate email gateway telemetry for Office attachments with endpoint process trees to identify weaponized delivery chains

Monitoring Recommendations

Ingest Microsoft Defender, Sysmon, and email security logs into a centralized data lake for cross-source correlation of document-borne activity
Monitor patch compliance across Microsoft 365 Apps and Office LTSC installations to confirm the November 2024 update is deployed
Track outbound network connections initiated by Office processes to identify command-and-control staging after successful exploitation

How to Mitigate CVE-2024-49031

Immediate Actions Required

Apply the November 2024 Microsoft security update for all affected Office and Microsoft 365 Apps channels as documented in the Microsoft Security Update Guide
Verify update deployment on macOS Office LTSC 2021 and 2024 installations, which are also affected
Enable Protected View and Office Application Guard for documents originating from the internet or email

Patch Information

Microsoft released fixes for CVE-2024-49031 on November 12, 2024, through the standard Microsoft 365 Apps update channels and the Microsoft Update Catalog for Office 2016, Office 2019, and Office LTSC 2021 and 2024. Administrators should confirm the corresponding build numbers listed in the Microsoft Security Update Guide for CVE-2024-49031 are installed on all endpoints before considering the vulnerability remediated.

Workarounds

Block or quarantine Office document attachments from untrusted senders at the mail gateway until patching completes
Enforce Attack Surface Reduction (ASR) rules that block Office applications from creating child processes and from injecting into other processes
Restrict opening of documents from the internet by keeping Protected View enabled and Mark-of-the-Web enforcement in place

bash

# Enable Microsoft Defender ASR rules that reduce Office exploitation impact
# Block Office applications from creating child processes
Set-MpPreference -AttackSurfaceReductionRules_Ids D4F940AB-401B-4EFC-AADC-AD5F3C50688A -AttackSurfaceReductionRules_Actions Enabled

# Block Office applications from injecting code into other processes
Set-MpPreference -AttackSurfaceReductionRules_Ids 75668C1F-73B5-4CF0-BB93-3ECF5CB7CC84 -AttackSurfaceReductionRules_Actions Enabled

# Block executable content from email client and webmail
Set-MpPreference -AttackSurfaceReductionRules_Ids BE9BA2D9-53EA-4CDC-84E5-9B1EEEE46550 -AttackSurfaceReductionRules_Actions Enabled