Almost five million combinations of Gmail addresses and passwords were posted online on Tuesday wherein the passwords seemed old and did not appear to belong to Gmail accounts.
According to some security experts, the addresses seemed to have been taken from websites where users give Gmail addresses to register.
Most of the passwords leaked seemed to be 'mypassword' while users' actual passwords might be different.
The list comprising Gmail addresses and passwords was posted on a Russia Bitcoin forum on Tuesday, reported stuff.co.nz.
However, the authenticity of the addresses and passwords could not be confirmed.
Many Reddit users said that their Gmail addresses were there but their passwords were incorrect.