Are open redirects a security concern? Google writes that: "An open redirect isn't a bug or a security flaw in and of itself—for some uses they have to be left fairly open." And Google's bounty program doesn't view it as a bug:
Some members of the security community argue that open redirectors are a security issue. The common argument in favor of this view is that some users, when presented with a carefully crafted link, may be duped into thinking that they will be taken to a trusted page - but will be not be attentive enough to examine the contents of the address bar after the redirection takes place.
Should open redirects be treated as bugs?