ZDI-26-587: Ashlar-Vellum Cobalt VS 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 specific flaw exists within the parsing of VS files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process.
Other sources
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-2026-19781.
— ZDI
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Ashlar-Vellum Cobaltto a version that resolves this vulnerability.Patch ZDI-26-587
Event History
Frequently Asked Questions
What must an attacker do to exploit this vulnerability?
An attacker must induce the target to visit a malicious page or open a malicious file. Successful exploitation can allow the attacker to execute arbitrary code on the affected installation.
Who is exposed to this issue?
Users of affected Ashlar-Vellum Cobalt installations are exposed when they interact with attacker-controlled pages or files. The provided information does not identify affected versions or configuration-specific conditions.
How severe is the issue?
ZDI assigned this vulnerability a CVSS score of 7.8. It is tracked as CVE-2026-19781.