One heavy request,everyone waits.
Not every flaw is about getting in. Some let a stranger tie your site up with a few requests the software was never built for, so real visitors cannot get through.
What it is
Software expects sensible input. With this kind of flaw, certain input makes it do far more work than it should: a calculation that never finishes, or memory that keeps filling up. A handful of such requests is enough to keep the server busy.
What could happen to your site
The site slows to a crawl or stops answering for as long as the requests keep coming. Nothing is stolen and nothing is changed, but a shop that will not load loses sales, and a site that keeps falling over can slip down in Google.
How likely it is
Common in script libraries and server software, and usually graded Minor or Major because no data is at risk. It is cheap to try, though, and it is sometimes used as a nuisance or to cover other mischief.
How it gets fixed
Update to the fixed version, which puts a limit on the work the software will do. A firewall service in front of the site can also soak up floods of requests, and many hosts include one.
What to ask your developer
Send whoever looks after your site this:
Ask your developer“The Mendbird report says some of our software has a flaw that could let someone knock the site over. Can you update it the next time you work on the site?”