The only thing that makes WebAssembly safer than its predecessors, is that most security researchers haven't yet bothered with it.
Bugs exist everywhere. Of course you finde some if you put in the effort. That is not something that marks the quality of the code.
Wasm vulnerabilities are worth real money. Bug bounties are tens of thousands of dollars to hundreds of thousands as part of exploit chains. If people aren't finding many, your explanation will have to be a little bit better than "they haven't yet bothered".
https://i.blackhat.com/us-18/Thu-August-9/us-18-Lukasiewicz-...
If you have real criticism based on real information, let's see it.
https://www.contextis.com/en/blog/webgl-a-new-dimension-for-...
https://react-etc.net/entry/exploiting-speculative-execution...
https://www.virusbulletin.com/virusbulletin/2018/10/dark-sid...
https://www.cvedetails.com/vulnerability-list/vendor_id-2041...
https://i.blackhat.com/us-18/Thu-August-9/us-18-Lukasiewicz-...
The first is about webgl (that has nothing to do with webasm)
The second is about using javascript with intel speculative execution exploits.
The third is grasping at straws, saying that call center scams would be more obsfuscated, even though javascript or asm.js can be just as obsfuscated, if not more.
The fourth is about crashes in the webasm JIT
The last is about -theoretically- executing arbitrary javascript. Heavens no.
What is the real reason you have some crazy crusade against webasm? You go to great lengths to grasp at any straws you can. It isn't that big of a deal. It is a more direct way to JIT cpu intensive parts of a web page. Get over it. Incredibly, the alternative is to run actual native instructions by downloading a binary.
Funneling your own frustrations into lying and spreading false information on the internet is not something a reasonable, emotionally healthy person does. Think about all the other people that do that in other areas of discussion. Those are your peers when you do this.
In fact I rejoice that WebAssembly, despite all the attempts to be presented as safe and novel, is becoming the mechanism to bring back to life all the plugins that where killed in name of WebAssembly.
I will give 5 years time for WebGL/WebGPU + WebAssembly to rule the majority of multimedia driven websites, with a new generation of Flash like tooling.
Then you call tell the world how much safer and novel WebAssembly is.