CVE-2023-37418: 
NixOS vulnerability analysis and mitigation

Multiple out-of-bounds write vulnerabilities exist in the VCD parsevaluechange portdump functionality of GTKWave 3.3.115. The vulnerability (CVE-2023-37418) specifically concerns the out-of-bounds write when triggered via the vcd2vzt conversion utility. A specially crafted .vcd file can lead to arbitrary code execution, requiring a victim to open a malicious file to trigger these vulnerabilities ([Talos Report](https://talosintelligence.com/vulnerabilityreports/TALOS-2023-1804)).

The vulnerability exists in the vcd2vzt conversion utility's buffer handling mechanism. The issue occurs when processing VCD files, specifically in the parsevaluechange function. The vulnerability stems from an incorrect buffer size check that only reallocates if vector has a size smaller than vsize, whereas it should check for yylencache <= v->size. This allows the strcpy operation to write one NULL byte out-of-bounds in the heap. The vulnerability has been assigned a CVSS v3.1 Base Score of 7.8 HIGH with vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (NVD).

The vulnerability can lead to arbitrary code execution on the targeted system. Through careful heap manipulation, which is feasible due to controllable allocations in the parser via file contents, an attacker can potentially execute arbitrary code on the affected system (Talos Report).

The vulnerability has been fixed in GTKWave version 3.3.118. Users are advised to upgrade to this version or later. Multiple distributions have released security updates to address this vulnerability, including Debian which has released updates for various versions (Debian LTS).