CVE-2025-15412 is a security vulnerability identified in the WebAssembly Binary Toolkit (wabt), a widely used open-source toolset for WebAssembly binary manipulation and analysis. The flaw exists in the function wabt::Decompiler::VarName within the wasm-decompile component, which is responsible for converting WebAssembly binaries back into a human-readable format. The vulnerability manifests as an out-of-bounds read, where the function reads memory beyond the allocated buffer boundaries. This can lead to unintended disclosure of memory contents or cause the application to crash, potentially impacting the confidentiality and availability of the system running the tool. The issue affects all versions of wabt up to and including 1.0.39. Exploitation requires local access with low privileges and does not require user interaction, making it a local privilege escalation or information disclosure risk in environments where untrusted users have local system access. The project currently lacks an active maintainer, and no official patches have been released, though the vulnerability has been publicly disclosed and a community member suggested that researchers submit a pull request to fix it. The CVSS 4.0 vector indicates low attack complexity, no user interaction, and partial impact on confidentiality, integrity, and availability, resulting in a medium severity rating. Given wabt’s role in WebAssembly development and analysis pipelines, this vulnerability poses a risk primarily in developer workstations, continuous integration environments, or any system where untrusted local users can execute wasm-decompile.

The primary impact of CVE-2025-15412 is the potential for information disclosure through out-of-bounds memory reads, which could expose sensitive data residing in adjacent memory areas. Additionally, the vulnerability could cause crashes or instability in the wasm-decompile tool, affecting availability. Since exploitation requires local access, the threat is mainly to environments where multiple users share systems or where attackers have gained limited local access. This could include developer machines, build servers, or CI/CD pipelines that incorporate wabt for WebAssembly analysis. The lack of an active maintainer and absence of official patches increases the risk of prolonged exposure. Organizations relying on wabt for WebAssembly tooling may face risks of data leakage or denial of service in their development or analysis workflows. However, the vulnerability does not directly affect production WebAssembly runtimes or end-user environments, limiting its scope. Still, attackers with local access could leverage this flaw as part of a broader attack chain to escalate privileges or gather intelligence.

Given the absence of an official patch, organizations should implement strict access controls to limit local access to systems running wabt, especially the wasm-decompile tool. Use role-based access control (RBAC) and enforce least privilege principles to prevent untrusted users from executing the vulnerable component. Monitor and audit usage of wabt binaries to detect unusual or unauthorized activity. Consider isolating WebAssembly development and analysis environments from sensitive networks and data. If feasible, review the source code of wabt::Decompiler::VarName and develop an internal patch or workaround to validate input sizes and prevent out-of-bounds reads. Engage with the open-source community to contribute fixes or track any emerging patches. Additionally, containerizing the wabt tool with strict resource and memory limits can reduce the impact of potential crashes. Finally, educate developers and system administrators about the vulnerability and the importance of controlling local access to development tools.