CVE-2025-6274 is a medium-severity vulnerability affecting the WebAssembly Binary Toolkit (wabt) versions 1.0.0 through 1.0.37. The vulnerability resides in the OnDataCount function within the src/interp/binary-reader-interp.cc source file. It is characterized as a resource consumption issue, which can be triggered by manipulating input data to cause excessive resource usage during WebAssembly binary interpretation. The vulnerability requires local access with low privileges (local attack vector with low complexity) and does not require user interaction or authentication beyond local access. The CVSS 4.0 base score is 4.8, reflecting a medium impact primarily on availability due to resource exhaustion. Although an exploit has been publicly disclosed, there are no known exploits currently observed in the wild. Additionally, the maintainer has disputed a similar issue, suggesting that the practical impact on real-world WebAssembly programs may be limited, which could also apply to this vulnerability. The vulnerability does not affect confidentiality or integrity, and the scope is limited to the wabt tool, which is primarily used by developers and toolchains working with WebAssembly binaries rather than end-user applications. No official patches have been linked yet, so mitigation currently relies on limiting local access and monitoring resource usage during wabt operations.

For European organizations, the impact of CVE-2025-6274 is primarily related to development and build environments that utilize the wabt tool for WebAssembly binary processing. Since wabt is a developer tool rather than a runtime environment, the direct risk to production systems is limited. However, organizations heavily invested in WebAssembly development, such as software vendors, cloud service providers offering WebAssembly execution environments, and research institutions, could experience denial-of-service conditions on developer machines or build servers if exploited locally. This could lead to delays in development cycles or resource exhaustion on critical build infrastructure. The vulnerability does not pose a direct threat to confidentiality or data integrity but could indirectly affect availability of development resources. Given the local attack vector requirement, the threat is more relevant in environments where multiple users have local access or where attacker footholds have already been established. European organizations with strict internal access controls and segmented development environments will be less exposed. The lack of known exploits in the wild and the disputed practical impact reduce the immediate urgency but do not eliminate the need for caution in sensitive or high-availability development contexts.

1. Restrict local access to systems running wabt to trusted users only, minimizing the risk of local exploitation. 2. Monitor resource consumption on developer and build machines when processing WebAssembly binaries with wabt to detect abnormal spikes indicative of exploitation attempts. 3. Isolate build environments and use containerization or virtual machines to limit the impact of potential resource exhaustion. 4. Stay updated with the wabt project for official patches or updates addressing this vulnerability and apply them promptly once available. 5. Implement strict code review and validation of WebAssembly binaries processed by wabt to avoid malformed inputs that could trigger the vulnerability. 6. Consider alternative WebAssembly tools or updated versions if they provide improved resilience against resource consumption issues. 7. Educate developers and system administrators about the vulnerability and the importance of limiting local access and monitoring resource usage.