CVE-2023-35989 in GTKWave
Summary
by MITRE • 01/08/2024
An integer overflow vulnerability exists in the LXT2 zlib block allocation functionality of GTKWave 3.3.115. A specially crafted .lxt2 file can lead to arbitrary code execution. A victim would need to open a malicious file to trigger this vulnerability.
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Analysis
by VulDB Data Team • 08/29/2025
The integer overflow vulnerability identified as CVE-2023-35989 resides within the LXT2 zlib block allocation mechanism of GTKWave version 3.3.115. This flaw represents a critical security weakness that can be exploited through maliciously crafted .lxt2 waveform files. The vulnerability stems from inadequate input validation and arithmetic handling within the decompression and allocation routines that process LXT2 formatted data files. When GTKWave attempts to parse and render waveform data from these files, the integer overflow occurs during memory allocation calculations, creating a scenario where attacker-controlled data can manipulate the allocation process to cause memory corruption.
The technical exploitation of this vulnerability follows a specific attack pattern that aligns with common software security principles and attack frameworks such as those outlined in the MITRE ATT&CK framework under the T1203 technique for legitimate program execution. The flaw manifests when the application processes compressed data blocks that contain malformed integer values within their headers. These values, when interpreted as memory allocation sizes, exceed the maximum representable value for the integer type used in the allocation function, resulting in a wraparound condition. This overflow condition allows an attacker to manipulate the memory allocation process, potentially leading to buffer overflows or other memory corruption issues that can be leveraged for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple denial of service or data corruption scenarios. An attacker who successfully exploits this integer overflow can achieve remote code execution on systems where GTKWave is installed and configured to automatically open or process .lxt2 files. This presents a significant risk in environments where users might encounter malicious waveform files through various attack vectors including email attachments, web downloads, or compromised file sharing platforms. The vulnerability affects any system running GTKWave 3.3.115 or earlier versions, making it particularly concerning given the widespread use of this waveform viewer in digital design verification and simulation environments. The attack requires minimal user interaction beyond opening the malicious file, making it particularly dangerous in automated or semi-automated testing environments where file opening might be triggered programmatically.
Mitigation strategies for CVE-2023-35989 should prioritize immediate patching of affected GTKWave installations to version 3.3.116 or later, which contains the necessary fixes for the integer overflow condition. Organizations should implement strict file validation policies for .lxt2 files, particularly in environments where these files might be processed automatically or received from untrusted sources. The fix typically involves implementing proper bounds checking and integer overflow protection mechanisms in the allocation routines, ensuring that input values are validated against maximum representable limits before being used in memory allocation calculations. Security teams should also consider implementing network-based intrusion detection systems that can identify suspicious .lxt2 file patterns and monitor for potential exploitation attempts. Additionally, user education about the risks of opening unknown or untrusted waveform files remains crucial, as this vulnerability can be effectively exploited through social engineering campaigns targeting users who might inadvertently open malicious files. The vulnerability's classification under CWE-190, Integer Overflow or Wraparound, underscores the fundamental nature of the flaw and emphasizes the need for robust integer arithmetic validation throughout the application's codebase.