ZDI-CAN-28173: 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 to a fixed release to a version that resolves this vulnerability.
Patch ZDI-26-587 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch CVE-2026-19781
Event History
Frequently Asked Questions
What does an attacker need to do to exploit this issue?
The attacker must persuade a user of an affected installation to visit a malicious page or open a malicious file. Successful exploitation can result in arbitrary code execution.
How severe is this vulnerability?
ZDI assigned this issue a CVSS rating of 7.8. The vulnerability is tracked as CVE-2026-19781.