Vulnerable

From Late Latin vulnerÄbilis ("injurious, wounding"), from Latin vulnerÅ ("I wound").

Full definition of vulnerable

More or most likely to be exposed to the chance of being attacked or harmed, either physically or emotionally.

2012, June 29, Kevin Mitchell, Roger Federer back from Wimbledon 2012 brink to beat Julien Benneteau, The elimination of Federer after Nadal's loss to Lukas Rosol would have created mild panic among the fans of these gloriously gifted but now clearly vulnerable geniuses.
2013-07-19, Mark Tran, Denied an education by war, One particularly damaging, but often ignored, effect of conflict on education is the proliferation of attacks on schools...as children, teachers or school buildings become the targets of attacks. Parents fear sending their children to school. Girls are particularly vulnerable to sexual violence.

"You are vulnerable to be bullied by someone at school."
(computing) More likely to be exposed to malicious programs or viruses.
a vulnerable PC with no antivirus software