CVE-2023-38648: 
NixOS vulnerability analysis and mitigation

Multiple out-of-bounds write vulnerabilities exist in the VZT vzt_rd_get_facname decompression functionality of GTKWave 3.3.115. A specially crafted .vzt file can lead to arbitrary code execution. A victim would need to open a malicious file to trigger these vulnerabilities. This vulnerability specifically concerns the out-of-bounds write performed by the prefix copy loop (Talos Report).

The vulnerability exists in the VZT file parsing functionality, specifically in the vzt_rd_get_facname function. The issue occurs because bufprev and bufcurr buffers are allocated with a size of longestname + 1, which is a field defined in the input file. However, the size of these buffers is never validated when writing to them during the prefix copy loop and string copy operations. This allows attackers to perform out-of-bounds writes in the heap through specially crafted .vzt files. 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 (Talos Report).

If successfully exploited, this vulnerability can lead to arbitrary code execution on the target system. The attack requires user interaction, as the victim needs to open a malicious .vzt file to trigger the vulnerability (Talos Report).

The vulnerability has been fixed in GTKWave version 3.3.118. Users are advised to upgrade to this or later versions. The fix has been included in various distribution updates, including Debian's security updates (Debian LTS).