CVE-2025-62711 is a vulnerability identified in the Wasmtime WebAssembly runtime, specifically affecting versions from 38.0.0 up to but not including 38.0.3. Wasmtime facilitates running WebAssembly modules outside the browser, often used in cloud, edge computing, and embedded environments. The vulnerability arises from improper handling of exceptional conditions within the implementation of component-model related host-to-wasm trampolines. These trampolines are mechanisms that enable communication and function calls between host environments and WebAssembly components. An attacker can craft a malicious component that, when invoked in a particular manner, triggers a segmentation fault or assertion failure in the host process, causing it to crash. This results in a denial-of-service condition. The CVSS 4.0 vector indicates network attack vector (AV:N), high attack complexity (AC:H), partial privileges required (PR:L), user interaction needed (UI:P), and low impact on availability (VA:L), with no impact on confidentiality or integrity. No known exploits exist in the wild, and no workarounds are available aside from upgrading. The patch was released in Wasmtime 38.0.3, which corrects the exceptional condition handling to prevent host crashes. The vulnerability is classified under CWE-755, which relates to improper handling of exceptional conditions, emphasizing the importance of robust error management in runtime environments.

For European organizations, the primary impact of CVE-2025-62711 is the potential for denial-of-service (DoS) attacks against systems running vulnerable Wasmtime versions. This could disrupt services relying on WebAssembly modules, particularly in cloud-native applications, edge computing, and microservices architectures where Wasmtime is employed. While the vulnerability does not compromise data confidentiality or integrity, availability interruptions can affect business continuity, especially for critical infrastructure or real-time processing systems. Organizations using Wasmtime in production environments may experience unexpected crashes, leading to downtime and potential loss of customer trust. The requirement for user interaction and low privileges reduces the likelihood of widespread exploitation but does not eliminate risk, particularly in environments where untrusted components might be loaded or where attackers can induce user actions. The absence of known exploits suggests limited current threat activity, but the availability of a patch necessitates proactive remediation to prevent future exploitation. European entities with significant reliance on WebAssembly runtimes in sectors such as finance, telecommunications, and cloud services should prioritize addressing this vulnerability to maintain operational stability.

1. Upgrade Wasmtime to version 38.0.3 or later immediately to apply the official patch that resolves the improper exceptional condition handling. 2. Implement strict validation and sandboxing of WebAssembly components to prevent loading of untrusted or malicious modules that could exploit the vulnerability. 3. Monitor Wasmtime host processes for abnormal termination patterns or crashes indicative of exploitation attempts, integrating alerts into security information and event management (SIEM) systems. 4. Restrict access to Wasmtime runtime environments to trusted users and limit network exposure to reduce the attack surface. 5. Employ runtime integrity checks and automated restarts for Wasmtime services to minimize downtime in case of crashes. 6. Conduct security awareness training for developers and operators about the risks of loading unverified WebAssembly components and the importance of timely patching. 7. Review and update incident response plans to include scenarios involving denial-of-service via runtime crashes. 8. Engage with Wasmtime community and vendor advisories for ongoing updates and best practices related to WebAssembly security.