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, the cs_disasm or cs_disasm_iter functions perform a memcpy operation that can copy more than 24 bytes into the cs_insn.bytes buffer without verifying the buffer size, leading to heap memory corruption. This memory corruption can potentially be exploited to execute arbitrary code, cause application crashes, or leak sensitive information. The vulnerability 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 has a CVSS score of 4.8, categorized as medium severity. Although no known exploits are currently reported in the wild, the issue is critical for environments relying on capstone for security tooling. The vulnerability was fixed in a commit identified as cbef767ab33b82166d263895f24084b75b316df3, which implements proper bounds checking on the skipdata length parameter to prevent buffer overflow. Organizations using affected versions should upgrade to patched versions promptly to mitigate risks.

The heap-based buffer overflow vulnerability in capstone can lead to memory corruption, which may be leveraged to execute arbitrary code, cause denial of service through application crashes, or leak sensitive information processed during disassembly. For European organizations, especially those involved in cybersecurity research, malware analysis, and software development, this vulnerability poses a risk to the integrity and availability of their analysis tools. If exploited, attackers could compromise the security of systems performing binary analysis, potentially undermining incident response and threat hunting capabilities. Although exploitation requires local access and user interaction, insider threats or compromised user accounts could trigger the vulnerability. The medium CVSS score reflects moderate risk, but the strategic importance of affected tools in security operations elevates the potential impact. Additionally, compromised analysis tools could lead to incorrect threat assessments or delayed responses, indirectly affecting organizational security posture.

European organizations should immediately identify and inventory all instances of capstone-engine usage within their environments, including security tools, malware analysis platforms, and development environments. They should upgrade to the fixed version of capstone that includes the patch from commit cbef767ab33b82166d263895f24084b75b316df3 or later. If upgrading is not immediately feasible, organizations should implement strict access controls to limit local user privileges and restrict execution of untrusted skipdata callbacks. Employ application whitelisting and sandboxing techniques to isolate disassembly processes and prevent exploitation from user-supplied inputs. Regularly monitor logs for abnormal crashes or memory errors in tools using capstone, which could indicate attempted exploitation. Incorporate vulnerability scanning and software composition analysis in the software development lifecycle to detect vulnerable capstone versions. Finally, educate users and administrators about the risks of executing untrusted code or callbacks within analysis tools.