CVE-2012-4886 in Office 2012
Summary
by MITRE
Stack-based buffer overflow in wpsio.dll in Kingsoft WPS Office 2012 possibly 8.1.0.3238 allows remote attackers to execute arbitrary code via a long BSTR string.
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Analysis
by VulDB Data Team • 05/08/2026
The vulnerability identified as CVE-2012-4886 represents a critical stack-based buffer overflow flaw within the wpsio.dll component of Kingsoft WPS Office 2012 and potentially version 8.1.0.3238. This security weakness resides in the handling of BSTR (Basic String) data structures, which are commonly used in COM (Component Object Model) environments for string manipulation. The flaw occurs when the application processes malformed or excessively long BSTR strings without proper bounds checking, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized system control.
The technical implementation of this vulnerability stems from improper input validation within the wpsio.dll library, which is responsible for processing various document formats within the WPS Office suite. When a maliciously crafted BSTR string exceeds the allocated stack buffer space, it overflows into adjacent memory locations, potentially overwriting critical program execution data such as return addresses, function pointers, or other control structures. This type of vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue that has been a primary target for exploitation techniques since the early days of software security research. The vulnerability's remote exploitability means that attackers can trigger the condition through network-based attacks without requiring local system access, making it particularly dangerous in enterprise environments.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the capability to completely compromise affected systems. Successful exploitation can lead to privilege escalation, data theft, system persistence mechanisms, and lateral movement within network environments. The WPS Office application's widespread use across various industries and organizations amplifies the potential damage, as a single compromised system could serve as a foothold for broader attacks. According to ATT&CK framework category T1059 Command and Scripting Interpreter, this vulnerability could enable adversaries to establish persistent access through malicious code execution, while T1068 Exploitation for Privilege Escalation demonstrates how such buffer overflows can be leveraged to gain elevated system privileges. The attack surface is further expanded by the fact that WPS Office is commonly used for document sharing, making it a prime target for spear-phishing campaigns where attackers embed malicious content in seemingly legitimate documents.
Mitigation strategies for CVE-2012-4886 should focus on immediate patching of affected software versions, as the vendor has released updates to address this specific vulnerability. Organizations should implement network segmentation and access controls to limit the potential impact of successful exploitation attempts, while also deploying intrusion detection systems to monitor for suspicious network traffic patterns associated with exploitation attempts. Application whitelisting policies can help prevent execution of unauthorized code, and regular security assessments should include vulnerability scanning for similar buffer overflow conditions in other office productivity suites. Additionally, user education regarding suspicious document attachments and the importance of keeping software updated remains crucial in defending against this class of attack, as many exploitation attempts rely on social engineering components to deliver malicious payloads to vulnerable systems.