CVE-2006-4513 in wvWare
Summary
by MITRE
Multiple integer overflows in the WV library in wvWare (formerly mswordview) before 1.2.3, as used by AbiWord, KWord, and possibly other products, allow user-assisted remote attackers to execute arbitrary code via a crafted Microsoft Word (DOC) file that produces (1) large LFO clfolvl values in the wvGetLFO_records function or (2) a large LFO nolfo value in the wvGetFLO_PLF function.
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Analysis
by VulDB Data Team • 04/25/2026
The vulnerability identified as CVE-2006-4513 represents a critical security flaw in the wvWare library, which serves as a crucial component for handling Microsoft Word document formats across various open-source office suites including AbiWord and KWord. This vulnerability stems from improper handling of integer values during the parsing of Word document structures, specifically within the wvGetLFO_records and wvGetFLO_PLF functions. The issue affects versions of wvWare prior to 1.2.3, making it a long-standing concern that impacted numerous applications relying on this library for document compatibility. The vulnerability is classified under CWE-190 as an integer overflow, which occurs when an integer value exceeds its maximum representable range and wraps around to a negative value, creating unpredictable behavior in the affected software systems.
The technical implementation of this vulnerability exploits two distinct code paths within the wvWare library that process different types of Word document structures. The first scenario involves the wvGetLFO_records function where maliciously crafted documents can force the system to process extremely large LFO clfolvl values, while the second scenario occurs in the wvGetFLO_PLF function when a large LFO nolfo value is encountered. Both scenarios result in integer overflows that can trigger buffer overflows or other memory corruption issues within the application memory space. These overflows occur during the parsing of Word document headers and structure records, where the library fails to properly validate input parameters before performing arithmetic operations or memory allocations. The vulnerability is particularly dangerous because it can be triggered through user-assisted remote attacks, meaning an attacker can craft a malicious Word document that, when opened by an affected application, will execute arbitrary code on the target system.
The operational impact of CVE-2006-4513 extends beyond simple application crashes, presenting a significant threat to system security and integrity. When successfully exploited, this vulnerability allows remote attackers to execute arbitrary code with the privileges of the affected application, potentially leading to complete system compromise. The attack vector is particularly concerning because it leverages the normal document processing functionality that users expect to work safely, making it difficult to detect and prevent through traditional security measures. Applications using the vulnerable wvWare library become susceptible to code execution attacks that can be delivered through email attachments, web downloads, or any other means of document distribution. The vulnerability aligns with ATT&CK technique T1203 by enabling process injection and privilege escalation through malicious document processing, while also supporting T1059 for command and scripting interpreter usage in the context of the executed malicious code.
Mitigation strategies for this vulnerability primarily focus on immediate software updates and patches to bring affected applications to versions that include the necessary fixes for integer overflow handling. System administrators should prioritize updating all instances of AbiWord, KWord, and any other applications that depend on wvWare to versions 1.2.3 or later where the integer overflow protections have been implemented. Additional protective measures include implementing strict document validation policies, using sandboxing techniques for document processing, and deploying content filtering solutions that can detect and block potentially malicious Word documents. Organizations should also consider implementing network-based intrusion detection systems that can monitor for suspicious document handling patterns, as well as establishing robust patch management processes to ensure all affected systems receive timely updates. The vulnerability demonstrates the critical importance of proper input validation and integer handling in security-critical libraries, emphasizing that even seemingly benign document processing functions can become attack vectors when proper bounds checking is absent.