CVE-2025-2019 in Cobalt
Summary
by MITRE • 03/11/2025
Ashlar-Vellum Cobalt VC6 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 VC6 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. Was ZDI-CAN-25252.
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Analysis
by VulDB Data Team • 08/08/2025
This heap-based buffer overflow vulnerability resides in the Ashlar-Vellum Cobalt software's VC6 file parsing functionality, representing a critical security flaw that enables remote code execution. The vulnerability stems from insufficient input validation during the processing of VC6 files, which are commonly used for document exchange within the software ecosystem. When the application encounters a malformed VC6 file containing excessive data in a specific field, it fails to properly validate the data length before copying it into a heap-based buffer, creating an exploitable condition that can be leveraged by remote attackers.
The technical nature of this vulnerability aligns with CWE-121, heap-based buffer overflow, and presents a direct pathway for privilege escalation through remote code execution. Attackers can craft malicious VC6 files that, when opened by an unsuspecting user, trigger the buffer overflow condition in the application's memory management system. The vulnerability requires user interaction to be exploited, meaning that victims must either visit a malicious webpage hosting the compromised file or directly open the malicious VC6 document, making this a client-side attack vector that relies on social engineering tactics. This characteristic places the vulnerability in the ATT&CK framework under T1203 - Exploitation for Client Execution, where adversaries leverage software vulnerabilities to execute malicious code on target systems.
The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation can lead to complete system compromise and persistent access for threat actors. The heap-based nature of the buffer overflow provides attackers with significant flexibility in crafting payloads that can bypass modern exploit mitigations such as ASLR and DEP, potentially allowing for privilege escalation to system-level access. The vulnerability affects all versions of Ashlar-Vellum Cobalt that process VC6 files, making it particularly concerning for organizations that rely heavily on this document management platform. Given that VC6 files are commonly shared in professional environments, the attack surface is broad and the potential for widespread exploitation exists.
Mitigation strategies should focus on immediate patching of affected systems, as the vendor has likely released a security update addressing the specific buffer overflow condition. Network-based defenses can include implementing strict file type filtering and content inspection for VC6 files, particularly when they originate from untrusted sources. Organizations should also consider deploying application whitelisting solutions that restrict execution of untrusted VC6 files outside of controlled environments. The implementation of sandboxing mechanisms for document processing can provide an additional layer of protection, isolating potentially malicious VC6 file parsing within restricted execution environments. Regular security assessments should include vulnerability scanning for similar buffer overflow conditions in other file format parsers within the organization's software ecosystem, as this represents a common class of vulnerability that affects many commercial applications.