CVE-2025-6275 is a use-after-free vulnerability identified in the WebAssembly Binary Toolkit (wabt) up to version 1.0.37. The flaw exists specifically in the function GetFuncOffset within the source file src/interp/binary-reader-interp.cc. This vulnerability arises when the function improperly manages memory, leading to a use-after-free condition where a previously freed memory region is accessed. Such a flaw can cause undefined behavior including crashes, data corruption, or potentially arbitrary code execution. The vulnerability requires local access to the host system to be exploited, meaning an attacker must have some level of local privileges (low privileges) to trigger the flaw. No user interaction or authentication is required beyond local access. The vulnerability has a CVSS 4.0 base score of 4.8, categorized as medium severity, reflecting limited impact and exploitation complexity. The exploit has been publicly disclosed but there are no known exploits actively used in the wild. Additionally, the maintainer has disputed the practical impact of a similar issue, suggesting that real-world WebAssembly programs may not be affected, which could also apply to this vulnerability. Wabt is a widely used toolkit for WebAssembly development and debugging, often employed by developers and security researchers to inspect, manipulate, and validate WebAssembly binaries. The vulnerability could impact any environment where vulnerable versions of wabt are used locally, especially in development or testing scenarios involving WebAssembly modules.

For European organizations, the direct impact of CVE-2025-6275 is relatively limited due to the requirement for local access and the medium severity rating. However, organizations heavily involved in WebAssembly development, research, or deployment could face risks such as local privilege escalation or denial of service if an attacker gains local access to developer machines or build servers running vulnerable wabt versions. This could lead to disruption of development workflows or potential compromise of sensitive code or intellectual property. Since WebAssembly is increasingly used in web applications and cloud environments, any compromise in the toolchain could indirectly affect software supply chain integrity. Critical sectors such as finance, telecommunications, and technology companies in Europe that leverage WebAssembly for performance or security benefits might be more sensitive to disruptions. The lack of known active exploitation reduces immediate risk, but the public disclosure means attackers could develop exploits targeting vulnerable local environments. The disputed real-world impact suggests that the threat might be more theoretical than practical, but cautious organizations should not dismiss the risk entirely.

1. Upgrade to the latest version of wabt beyond 1.0.37 once patches are available or monitor official repositories for security updates addressing this vulnerability. 2. Restrict local access to systems running wabt, especially developer workstations and build servers, to trusted personnel only. 3. Implement strict access controls and endpoint security measures to prevent unauthorized local access or lateral movement within networks. 4. Use containerization or sandboxing techniques to isolate wabt usage environments, limiting the impact of any potential exploitation. 5. Conduct code reviews and static analysis on WebAssembly modules to detect suspicious or malformed inputs that might trigger the vulnerability during testing. 6. Monitor local system logs and behavior for anomalies that could indicate exploitation attempts, such as unexpected crashes or memory errors related to wabt processes. 7. Educate developers and security teams about the vulnerability and encourage best practices in handling WebAssembly binaries securely. 8. Consider alternative WebAssembly toolkits or utilities if immediate patching is not feasible and risk tolerance is low.