The phrase "are only vulnerable" is correct and usable in written English.
It can be used to describe a specific group or entity that has limited susceptibility to harm or attack.
Example: "In this scenario, the players are only vulnerable to attacks from the left flank."
Alternatives: "are merely susceptible" or "are solely at risk".
"You are only vulnerable if you want to sell and you need money.
Users are only vulnerable if they have a previously installed malicious application on their system that they have granted the "Read Sensitive Log Data" extended permission.
Users are only vulnerable if they are using an unsecured or untrusted public wireless network and an older version of the application.
"Facebook's iOS and Android applications are only intended for use with the manufacture provided operating system, and access tokens are only vulnerable if they have modified their mobile OS (i.e. jailbroken iOS or modded Android) or have granted a malicious actor access to the physical device.
Some foes are only vulnerable to certain moves.
Official U.S. PlayStation Magazine noted that the game's inventory was too limited for the vast number of customizations possible; this was considered particularly troublesome because some boss enemies are only vulnerable to certain types of weapons.
Mixed with the models were only vulnerable women, a coverage that amounted to, in Gottesman's opinion, "Victims and Vixens".
"A turtle is only vulnerable when he sticks his head out - when he senses danger, he goes back into that shell.
If you count others whose incomes or jobs are not exposed to the economic cycle, 49% of those either in work or retired are only moderately vulnerable to the recession, according to Xerfi, an economics consultancy.
The Kurdish Yazidis are only the latest vulnerable minority to need protection.
Currently, they are only listed as "Vulnerable" on the IUCN's (International Union for the Conservation of Nature) Red List of Threatened Species.
