As many as twelve million routers in use in homes and businesses around the world contain a bug that makes them vulnerable to a particular form of attack. Routers made by Linksys, D-Link, Edimax, Huawei, TP-Link, ZTE, ZyXEL and others are affected (see this list of affected routers – warning: PDF).

The vulnerability exists in a particular piece of software called RomPager. This software is embedded in the firmware of the affected routers.

Routers typically provide a mechanism for updating their firmware, but router manufacturers are often slow to provide updates, and the update process can be problematic, especially for regular users.

As a result, this problem is likely to hang around for years, and will not be completely eliminated until all of the affected routers are updated or replaced.