Comcast waited 13 days to patch its network against a high-severity vulnerability, a lapse that allowed hackers to make off with password data and other sensitive information belonging to 36 million Xfinity customers. The breach, which was carried out by exploiting a vulnerability in network hardware sold by Citrix, gave hackers access to usernames and cryptographically hashed passwords for 35.9 million Xfinity customers, the cable TV and Internet provider said in a notification filed Monday with the Maine attorney general’s office. Citrix disclosed the vulnerability and issued a patch on October 10. Eight days later, researchers reported that the vulnerability,…