CVE-2023-35128 is a high-severity integer overflow vulnerability identified in GTKWave version 3.3.115, specifically within the fstReaderIterBlocks2 function related to the time_table tsec_nitems processing. GTKWave is a widely used open-source waveform viewer for digital design verification, commonly employed by hardware engineers to analyze simulation output files. The vulnerability arises when GTKWave processes a specially crafted .fst (Fast Signal Trace) file. Due to improper handling of integer values, an overflow or wraparound can occur, leading to memory corruption. This memory corruption could potentially be exploited to execute arbitrary code, cause a denial of service, or crash the application. Exploitation requires a victim to open a malicious .fst file, which means user interaction is necessary. The CVSS v3.1 base score is 7.0, indicating a high severity level, with the vector AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H. This means the attack vector is local (the attacker must have local access), the attack complexity is high, no privileges are required, but user interaction is necessary. The scope is unchanged, and the impact on confidentiality, integrity, and availability is high. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability is classified under CWE-190 (Integer Overflow or Wraparound), a common weakness that can lead to serious memory safety issues if not properly mitigated.

For European organizations, the impact of this vulnerability depends largely on the use of GTKWave in their hardware design and verification workflows. Organizations involved in semiconductor design, embedded systems development, or academic research using GTKWave could face risks of application crashes, potential arbitrary code execution, or data corruption if malicious .fst files are opened. This could lead to loss of intellectual property, disruption of development processes, or compromise of systems if exploited in a targeted attack. Since the vulnerability requires opening a crafted file, the risk is primarily from insider threats or supply chain attacks where malicious files might be introduced. The high impact on confidentiality, integrity, and availability means sensitive design data could be exposed or altered, affecting product security and compliance with European data protection regulations. Additionally, disruption in development environments could delay product releases and increase costs. However, the local attack vector and high attack complexity reduce the likelihood of widespread exploitation, limiting the threat to environments where GTKWave is actively used and trusted files are handled.

European organizations should implement the following specific mitigations: 1) Restrict GTKWave usage to trusted personnel and environments to minimize exposure to malicious .fst files. 2) Implement strict file validation and scanning procedures for all .fst files before opening them in GTKWave, including sandboxing or opening files in isolated environments. 3) Monitor and control the distribution channels of .fst files, especially from external or third-party sources, to prevent supply chain insertion of malicious files. 4) Employ application whitelisting and endpoint protection solutions that can detect anomalous behavior or memory corruption attempts during GTKWave execution. 5) Maintain strict access controls on systems running GTKWave to prevent unauthorized local access, as exploitation requires local presence. 6) Stay alert for official patches or updates from GTKWave developers and apply them promptly once available. 7) Educate users about the risks of opening untrusted .fst files and enforce policies to avoid opening files from unknown sources. These measures go beyond generic advice by focusing on file handling policies, environment isolation, and access controls tailored to the specific attack vector and exploitation requirements of this vulnerability.