CVE-2026-69353 in Windows
Summary
by MITRE • 09/08/2026
Out-of-bounds read in Windows Text Shaping allows an authorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 09/08/2026
The vulnerability identified as an out-of-bounds read within the Windows Text Shaping subsystem represents a critical memory safety flaw that compromises the integrity of data processing during font rendering operations. This component is responsible for converting Unicode character sequences into visual glyphs, a process essential for displaying text correctly across various applications and system interfaces. The core technical issue stems from improper validation of input parameters or buffer boundaries when handling specific glyph metrics or layout calculations. When an attacker provides crafted input that triggers this flawed logic, the application attempts to read memory locations beyond the allocated buffer limits. This behavior is classified under CWE-125, which defines out-of-bounds read vulnerabilities where software reads data past the end of a buffer, potentially leading to information disclosure rather than immediate code execution in many scenarios involving text rendering engines.
The operational impact of this vulnerability centers on local information disclosure. Because the flaw allows an attacker to access memory contents that should remain inaccessible, sensitive data residing adjacent to the targeted buffer can be leaked. This may include internal application states, cryptographic keys, or other confidential user data processed by the affected system components. The requirement for authorization implies that a malicious actor must already have valid credentials and local access to exploit this condition, typically through a web browser or an office application that utilizes the Windows text shaping services. While it does not directly grant remote code execution capabilities, the leakage of sensitive information can facilitate further attacks by providing attackers with valuable context about the target environment, such as ASLR offsets or internal structures, thereby reducing the complexity of subsequent exploitation attempts against more critical system components.
From a threat modeling perspective aligned with MITRE ATT&CK frameworks, this vulnerability falls under techniques related to Collection and Exfiltration via Local Data Access. Specifically, it relates to methods where attackers harvest data from local systems without triggering traditional network-based detection mechanisms. The lack of robust boundary checks in the text shaping module highlights a common challenge in legacy codebases where performance optimizations sometimes bypass strict safety validations. To mitigate this risk, organizations must ensure that all affected Windows versions are updated with the latest security patches released by Microsoft. These updates typically include rigorous input validation and bounds checking within the text rendering pipeline to prevent unauthorized memory access. Additionally, implementing application whitelisting policies can restrict which applications have permission to interact with low-level system libraries like those involved in font processing, thereby reducing the attack surface available to potential exploiters even if they possess local user privileges.