CVE-2026-63513 in Office
Summary
by MITRE • 08/11/2026
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 08/11/2026
A heap-based buffer overflow vulnerability exists within Microsoft Office applications that enables remote code execution by exploiting memory corruption flaws in the software's handling of maliciously crafted Office documents. This vulnerability resides in the memory management subsystem where insufficient bounds checking occurs during processing of structured data elements such as tables, lists, or embedded objects within document formats like wordprocessingml or excel spreadsheet components. The flaw specifically manifests when the application attempts to write data beyond the allocated heap memory boundaries, creating a condition where attacker-controlled data can overwrite adjacent memory locations including function pointers, return addresses, or critical program variables.
The technical exploitation of this vulnerability follows established patterns described in common weakness enumeration cwe-121 and cwe-787 which categorize heap overflow conditions as direct memory corruption issues. Attackers typically craft specially formatted Office documents containing malicious payload data that triggers the buffer overflow when opened by vulnerable applications. The overflow can be leveraged to overwrite critical execution flow control elements in memory, enabling attackers to redirect program execution to malicious code injected into the process space. This technique aligns with attack pattern categories defined in mitre attack framework under tactic ta0002 execution and ta0005 defense evasion.
The operational impact of this vulnerability extends across multiple Microsoft Office products including word, excel, powerpoint, and access applications running on various windows operating systems. Successful exploitation can result in complete system compromise with privileges equivalent to the user running the vulnerable application. The vulnerability affects both desktop and server installations, making it particularly dangerous for enterprise environments where users may open malicious documents from email attachments or web downloads. Organizations face significant risk of data exfiltration, persistent backdoor installation, and lateral movement within network perimeters when this vulnerability is exploited.
Mitigation strategies should prioritize immediate patch deployment from microsoft security updates which address the underlying memory management flaws through improved bounds checking and memory allocation practices. Network segmentation and email filtering solutions can provide additional protection layers by preventing initial delivery of malicious documents to user workstations. Application control measures such as microsoft applocker or similar endpoint protection platforms can restrict execution of untrusted Office documents from potentially compromised sources. Regular security awareness training for end users regarding suspicious email attachments and web downloads remains critical in reducing successful exploitation attempts. System monitoring should focus on detecting anomalous memory allocation patterns, unexpected process behavior, and unusual network connections that may indicate exploitation activity. Organizations should also implement regular vulnerability scanning to identify unpatched systems and maintain comprehensive incident response procedures tailored to handle potential exploitation attempts targeting this class of memory corruption vulnerabilities.