CVE-2025-49705 Overview
CVE-2025-49705 is a heap-based buffer overflow vulnerability in Microsoft Office PowerPoint that allows an unauthorized attacker to execute code locally. The flaw is tracked under CWE-122 and affects multiple supported Office builds, including Microsoft 365 Apps, Office 2019, Office LTSC 2021, Office LTSC 2024, and PowerPoint 2016. Exploitation requires user interaction, typically opening a malicious PowerPoint file. Microsoft published the advisory on July 8, 2025.
Critical Impact
Successful exploitation grants attackers arbitrary code execution in the context of the user running PowerPoint, leading to full compromise of confidentiality, integrity, and availability on the local host.
Affected Products
- Microsoft 365 Apps (Enterprise, x64 and x86)
- Microsoft Office 2019 (x64 and x86)
- Microsoft Office LTSC 2021 and LTSC 2024 (Windows and macOS)
- Microsoft PowerPoint 2016
Discovery Timeline
- 2025-07-08 - CVE-2025-49705 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-49705
Vulnerability Analysis
The vulnerability is a heap-based buffer overflow (CWE-122) triggered when PowerPoint parses malformed presentation content. When the affected parser processes attacker-controlled structures, it writes past the bounds of a heap-allocated buffer, corrupting adjacent memory. Attackers who control the overflowing data can overwrite heap metadata or object pointers to redirect execution flow.
Code runs with the privileges of the user opening the file. Because Office applications routinely load embedded objects, fonts, and media, an unauthenticated attacker can weaponize a crafted .pptx or .ppt file and deliver it through email, cloud storage, or web downloads. The EPSS probability is 0.381% (29.9th percentile) as of the June 30, 2026 scoring.
Root Cause
The root cause is missing or insufficient bounds validation on a size or offset field consumed by PowerPoint's document parser. When the attacker supplies an oversized element, the allocator reserves a buffer sized from one field while the copy operation uses a different, untrusted length. This mismatch produces the out-of-bounds heap write required to corrupt control data.
Attack Vector
The attack vector is local and requires user interaction. The attacker crafts a malicious PowerPoint file and convinces the target to open it. Preview handlers and Protected View reduce, but do not eliminate, exposure because the vulnerable parsing code paths execute during document rendering. No network access or elevated privileges are needed prior to exploitation.
See the Microsoft Security Update CVE-2025-49705 advisory for vendor technical details.
Detection Methods for CVE-2025-49705
Indicators of Compromise
- PowerPoint files (.ppt, .pptx, .ppsx) received from untrusted senders or downloaded from unverified web sources.
- POWERPNT.EXE spawning unusual child processes such as cmd.exe, powershell.exe, rundll32.exe, or mshta.exe.
- Crash events or Windows Error Reporting entries citing heap corruption inside POWERPNT.EXE or Office parsing libraries.
- Unexpected outbound network connections initiated by POWERPNT.EXE shortly after a document is opened.
Detection Strategies
- Hunt for Office parent-to-shell child process relationships in endpoint telemetry, a common post-exploitation signal for Office memory corruption.
- Enable Microsoft Defender Attack Surface Reduction (ASR) rules that block Office applications from creating child processes and injecting into other processes.
- Deploy YARA or content inspection rules at mail and web gateways to flag PowerPoint files with malformed OOXML structures or embedded OLE objects.
Monitoring Recommendations
- Audit process creation logs (Sysmon Event ID 1, Windows 4688) for anomalous descendants of Office binaries.
- Correlate document open events with subsequent file writes to %TEMP%, %APPDATA%, and Startup folders.
- Monitor for Office application crashes tied to heap corruption and preserve dumps for forensic review.
How to Mitigate CVE-2025-49705
Immediate Actions Required
- Apply the July 2025 Microsoft security updates for all affected Office and Microsoft 365 Apps channels without delay.
- Verify patch deployment across managed endpoints, including macOS installations of Office LTSC 2021 and 2024.
- Restrict receipt of PowerPoint attachments from external senders until patching is confirmed.
- Enable Protected View and Office Application Guard for documents originating from the internet or email.
Patch Information
Microsoft released fixes as part of its Patch Tuesday updates. Refer to the Microsoft Security Update CVE-2025-49705 advisory for the specific build numbers per channel. Microsoft 365 Apps users on Current Channel should confirm the update by checking File > Account > Update Options > Update Now.
Workarounds
- Enforce Protected View for files from the internet, unsafe locations, and Outlook attachments through Group Policy.
- Block or quarantine PowerPoint attachments at the email gateway pending patch validation.
- Configure ASR rules to block child process creation from Office applications, reducing post-exploitation options.
- Disable macros and OLE object activation for users who do not require them.
# Example: Enforce Protected View via Group Policy registry keys (Office 16.0)
reg add "HKCU\Software\Policies\Microsoft\Office\16.0\PowerPoint\Security\ProtectedView" /v DisableInternetFilesInPV /t REG_DWORD /d 0 /f
reg add "HKCU\Software\Policies\Microsoft\Office\16.0\PowerPoint\Security\ProtectedView" /v DisableAttachmentsInPV /t REG_DWORD /d 0 /f
reg add "HKCU\Software\Policies\Microsoft\Office\16.0\PowerPoint\Security\ProtectedView" /v DisableUnsafeLocationsInPV /t REG_DWORD /d 0 /f
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
