The routers that dozens of hotel chains worldwide rely on to run their wireless networks have a flaw that opens them to attack, according to digital security firm Cylance.
The system flaw could enable a hacker to spread malware through a hotel's wifi network to guest computers. A hacker could also track and save data sent over the network, and maybe attack the hotel's Internet-connected operational systems.
Under question is the firmware of a bunch of models of InnGate wifi routers made by ANTlabs, according to an article in Wired (US).
In a press release, Cylance says:

"This vulnerability affects 277 hotels, convention centers and data centers across 29 countries....
ANTlabs is making a patch available today for its InnGate product. For more information about how to apply necessary protections for your hotel wifi, visit antlabs.com."
The industry standard for security alerts, Carnegie Mellon University's CERT, has issued a vulnerability warning.
MORE: Big Vulnerability in Hotel Wi-Fi Router Puts Guests at Risk