The Problems and Promise of WebAssembly (Project Zero)

Over at Google's Project Zero blog, Natalie Silvanovich looks at some of the bugs the project has found in WebAssembly, which is a binary format to run code in the browser for web applications. She also looks to the future: "There are two emerging features of WebAssembly that are likely to have a security impact. One is threading. Currently, WebAssembly only supports concurrency via JavaScript workers, but this is likely to change. Since JavaScript is designed assuming that this is the only concurrency model, WebAssembly threading has the potential to require a lot of code to be thread safe that did not previously need to be, and this could lead to security problems.WebAssembly GC [garbage collection] is another potential feature of WebAssembly that could lead to security problems. Currently, some uses of WebAssembly have performance problems due to the lack of higher-level memory management in WebAssembly. For example, it is difficult to implement a performant Java Virtual Machine in WebAssembly. If WebAssembly GC is implemented, it will increase the number of applications that WebAssembly can be used for, but it will also make it more likely that vulnerabilities related to memory management will occur in both WebAssembly engines and applications written in WebAssembly."