CVE-2026-63529 in 365 Apps for Enterprise
Summary
by MITRE • 08/11/2026
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical out-of-bounds read flaw within Microsoft Office applications that enables unauthorized attackers to extract sensitive information from the local system. The technical nature of this issue stems from improper input validation and memory management within the office suite's processing components, particularly affecting document parsing and rendering functions. When maliciously crafted files are opened or processed by vulnerable Office versions, the application fails to properly bounds-check array accesses or buffer operations, allowing memory reads beyond allocated boundaries. This weakness manifests as an information disclosure vulnerability that can be exploited through various attack vectors including email attachments, shared documents, or malicious file downloads. The flaw operates at the kernel and user-mode levels, leveraging legitimate application functionality to access memory regions that should remain protected from unauthorized reading.
The operational impact of this vulnerability extends beyond simple data exposure, potentially enabling attackers to extract sensitive system information, credentials, or proprietary data stored in adjacent memory locations. Attackers can leverage this weakness to perform reconnaissance activities, gather system configuration details, or obtain cryptographic keys and authentication tokens that may be cached in memory. The vulnerability's exploitation typically requires social engineering techniques to deliver malicious documents to target users, though automated exploitation methods have been documented in various threat campaigns. Security researchers have identified this issue as aligning with CWE-129, which addresses improper validation of array index values, and potentially CWE-787, concerning out-of-bounds write operations that can lead to information disclosure. The attack pattern follows ATT&CK technique T1059 for command and scripting interpreter usage and T1068 for exploit for privilege escalation, as attackers may use the information disclosed to plan more sophisticated attacks.
Mitigation strategies for this vulnerability encompass multiple layers of defense including immediate patch deployment from Microsoft security updates, implementation of application whitelisting policies, network-based intrusion detection system rules, and user education programs focused on identifying suspicious email attachments. Organizations should prioritize patch management processes to ensure all office applications remain current with security fixes, while implementing strict file validation controls at network perimeters. Additional protective measures include enabling exploit protection features such as address space layout randomization, data execution prevention, and controlled folder access policies that limit potential damage from successful exploitation attempts. Security teams must also monitor for indicators of compromise including unusual network traffic patterns or unauthorized file access attempts that may signal exploitation activity targeting this specific vulnerability. The remediation process requires careful coordination between IT operations and security teams to balance operational continuity with comprehensive vulnerability resolution, particularly in enterprise environments where legacy systems may require extended support periods while transitioning to patched configurations.