A Bing Forum thread has Wil from Bing telling a webmaster that it can take between 3 and 6 weeks to have a malware label removed from the search results.

This is in comparison to Google which normally can remove a malware label within 24 hours.

I am not sure if this is a special case or if most Malware reviews take 3-6 weeks at Bing. Wil from Bing said:

When you are presented with Malware via Bing, Bing disables the link but does allow the searcher to ultimately visit the page at their own risk. I’d assume 99.999% of those searchers run.

Bing has a detailed post on Malware on their blog with more information.

Malware and hacked sites are a huge issue in search. Google has been very good at handling it for the most part recently and is excellent at removing the malware or hacked label quickly after the site is fixed. Bing takes 3-6 weeks? Well, that seems excessive. Maybe I am reading it wrong?

Forum discussion at Bing Forum.