Heap-based Buffer Overflow Vulnerability in Ashlar-Vellum Cobalt
CVE-2026-121743

7.8HIGH

Key Information:

Vendor

Ashlar-vellum

Status
Cobalt
Vendor
CVE Published:
12 November 2026

What is CVE-2026-121743?

A vulnerability in Ashlar-Vellum Cobalt allows remote attackers to execute arbitrary code through a heap-based buffer overflow. This flaw arises from inadequate validation of user-supplied data length during AR file parsing. An attacker must entice a user to open a compromised file or visit a malicious webpage to trigger the exploit. Successful exploitation could enable execution of arbitrary code within the context of the affected process.

Affected Version(s)

Cobalt 1204.209

References

https://www.zerodayinitiative.com/advisories/ZDI-26-873/
x_research-advisory

CVSS V3.0

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.