CVE-2026-102210 in Windows
Summary
by MITRE • 10/13/2026
Heap-based buffer overflow in Windows Text Shaping allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described constitutes a critical security flaw within the Microsoft Windows operating system, specifically located in the text shaping subsystem responsible for rendering complex scripts and typography. This component is integral to how applications display characters that require contextual positioning or ligature formation, such as Arabic, Indic, or other non-Latin scripts. The core technical issue is identified as a heap-based buffer overflow, which occurs when an application writes more data to a block of memory allocated on the heap than it can hold. In this specific context, maliciously crafted input containing specially formatted text strings triggers an out-of-bounds write operation within the internal buffers managed by the Windows Text Shaping engine. This flaw allows for arbitrary code execution because the attacker can overwrite adjacent memory structures, potentially including function pointers or exception handling records, thereby hijacking the control flow of the process running with elevated privileges.
From a technical perspective, heap-based buffer overflows are particularly dangerous due to their potential for remote exploitation and stability impact compared to stack-based variants. The vulnerability likely stems from insufficient validation of input data lengths before copying them into fixed-size buffers within the text shaping library. When an attacker sends a network packet containing malformed Unicode sequences or specific glyph cluster information, the system attempts to process this data without adequate bounds checking. This leads to memory corruption that can be leveraged to execute arbitrary code on the target machine. The impact is severe as it allows unauthorized attackers to gain full control over the affected system, install malware, steal sensitive information, or establish a persistent foothold for further lateral movement within a network environment.
In terms of industry standard classifications, this vulnerability aligns with Common Weakness Enumeration identifier CWE-120, which denotes Buffer Copy without Checking Size of Input. This category highlights failures in input validation where the size of user-controlled data is not verified against the capacity of the destination buffer prior to copying operations. Furthermore, from a tactical standpoint related to the MITRE ATT&CK framework, this vulnerability facilitates initial access and execution phases through techniques associated with remote code execution via exploited applications or services. Attackers would typically leverage this flaw during the exploitation phase by crafting malicious documents or web content that triggers the vulnerable text shaping routines when rendered by affected Windows components such as Internet Explorer, Edge, or other applications relying on GDI+ for rendering complex scripts.
The operational impact of this vulnerability extends beyond immediate code execution to include potential denial of service conditions if the overflow causes a crash in critical system processes before exploitation is successful. However, given the nature of heap overflows and modern memory protection mechanisms like Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR), reliable exploitation requires precise control over memory layout and often involves bypassing these mitigations through sophisticated techniques such as information disclosure or partial overwrite attacks. Organizations must recognize that this vulnerability represents a high-severity risk, particularly for environments where users frequently interact with untrusted content from the internet or email systems that render rich text formats.
Mitigation strategies primarily involve applying vendor-supplied security patches and updates released by Microsoft to address the underlying code defects in the Windows Text Shaping library. Administrators should ensure that all workstations and servers are updated to the latest cumulative update versions which include fixes for this specific flaw. Additionally, defense-in-depth measures such as enabling Enhanced Security Configuration modes in browsers, restricting user privileges to standard accounts rather than administrators, and deploying endpoint detection and response solutions can significantly reduce the likelihood of successful exploitation. Network segmentation should also be considered to limit exposure to untrusted networks where malicious content might originate, thereby reducing the attack surface available to potential adversaries seeking to leverage this vulnerability for remote code execution.