I’d agree that ReDoS is a repeat offender in having overblown severity in vulnerability reports, and prototype pollution reports have contributed to a fair bit of noise when popping up in dev-tools and such, but prototype pollution can be quite significant.

Java has its “gadget chain” class of vulnerabilities, where the presence of certain jars can turn object deserialisation into RCEs. I’d argue that Javascript has “pollution gadgets”.

Some years ago I struggled making lodash – which almost any non-trivially sized Javascript project has at least a transitive dependency on (possibly multiple versions of) – fix its “gadget” in its template function. It’s since been patched, and the conversation unfortunately deleted - https://github.com/lodash/lodash/pull/4518

Here’s two real world examples of turning a prototype pollution into an RCE: https://hackerone.com/reports/852613 and https://hackerone.com/reports/861744

(If you’re unfamiliar with prototype pollution: This is possibly a security bug in Javascript: `obj[a][b] = c` if a user controls a, b and c.)