CVE-2025-67873 is a heap-based buffer overflow vulnerability identified in the capstone disassembly framework, specifically affecting versions 6.0.0-Alpha5 and earlier. Capstone is widely used for binary disassembly in security research, malware analysis, and reverse engineering. The vulnerability stems from improper bounds checking of the skipdata length parameter within the skipdata callback function. When a user-supplied skipdata callback is invoked during disassembly via cs_disasm or cs_disasm_iter, the memcpy operation can copy more than 24 bytes into the cs_insn.bytes buffer, exceeding its allocated heap space. This overflow can corrupt adjacent heap memory, potentially leading to arbitrary code execution, denial of service, or information disclosure depending on the context of use. Exploitation requires local access with low privileges and some user interaction, as indicated by the CVSS vector (AV:L/AC:L/PR:L/UI:R). The vulnerability is classified under CWE-122 (Heap-based Buffer Overflow). Although no known exploits are currently reported in the wild, the flaw poses a risk to environments where capstone is integrated into security tools or automated analysis pipelines. The issue was addressed in a commit identified as cbef767ab33b82166d263895f24084b75b316df3, which implements proper bounds checking to prevent overflow. Organizations using vulnerable versions should apply this fix or upgrade to a secure release. Due to the nature of the vulnerability, attackers with local access could leverage it to compromise system integrity or cause crashes, impacting the reliability of security analysis workflows.

For European organizations, the impact of CVE-2025-67873 depends largely on the deployment of capstone within their security infrastructure. Organizations involved in cybersecurity research, malware analysis, reverse engineering, or software development that utilize capstone could face risks of system crashes, data corruption, or potential privilege escalation if the vulnerability is exploited. The heap overflow could allow attackers to execute arbitrary code or disrupt disassembly processes, undermining the integrity and availability of critical analysis tools. This may lead to delays in threat detection or forensic investigations. Although exploitation requires local access and user interaction, insider threats or compromised user accounts could facilitate attacks. The confidentiality of sensitive analysis data might also be at risk if memory corruption leads to information leakage. Given the medium CVSS score and the requirement for local access, the threat is moderate but should not be underestimated in high-security environments. Failure to patch could expose organizations to targeted attacks aiming to disable or manipulate security tooling, which is particularly concerning for critical infrastructure operators and government agencies in Europe.

1. Upgrade capstone to a version later than 6.0.0-Alpha5 that includes the fix from commit cbef767ab33b82166d263895f24084b75b316df3. 2. If upgrading is not immediately possible, apply the patch manually to enforce bounds checking on skipdata length in the skipdata callback. 3. Restrict local access to systems running capstone-based tools to trusted users only, minimizing the risk of exploitation by unprivileged users. 4. Implement strict user account controls and monitor for unusual user activity that might indicate attempts to exploit the vulnerability. 5. Employ application whitelisting and integrity monitoring on security analysis tools to detect unauthorized modifications or crashes. 6. Conduct regular security audits of software dependencies, especially those used in critical analysis workflows, to ensure timely patching of vulnerabilities. 7. Educate security analysts and developers about the risks of using vulnerable versions and encourage best practices in handling third-party libraries. 8. Consider sandboxing or isolating disassembly processes to limit the impact of potential memory corruption.