ASHLAR-VELLUM COBALT · CVE-2026-121744 · Other
NO FIX YET · SEE WHAT TO DO
ZDI published a 0-day: Cobalt copies data from XE files into a fixed stack buffer without checking its length (stack-based buffer overflow). A user who opens a crafted XE file, or visits a malicious page that leads to one, can let the attacker run code in the context of the Cobalt process. ZDI says the vendor has not released a fix; its only mitigation is to restrict interaction with the product.
first public Nov 12, 2026 · 2 sources
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Teams that run Ashlar-Vellum Cobalt and open XE files from outside sources are exposed, since the user must open a malicious file or visit a malicious page. Installations that only handle trusted XE files are less exposed. The sources do not name affected versions.
Not affected if no-untrusted-xe-files, no-xe-files-opened
Who cares ashlar-vellum, cad, cobalt, file-parsing, no-fix, windows
Ashlar-Vellum Cobalt XE File Parsing Stack-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 specific flaw exists within the parsing of XE files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-28172.
This page as .md · .json · CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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