ZDI-CAN-28675: ZDI-26-873: (0Day) Ashlar-Vellum Cobalt AR File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Ashlar-Vellum Cobalt. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The ZDI has assigned a CVSS rating of 7.8. The following CVEs are assigned: CVE-2026-121743.