Yahoo encountered a similiar security problem less than 3 months ago.
Yahoo has confirmed that it has been working on a vulnerability to its email service that may be connected to the rise of hacked email accounts which have been used todeliver spam and other unwarranted content.
A Yahoo spokeswoman told All Things D that the firm heavily invests in measures to protect its users and their data.
"We were recently informed of an online video that demonstrated a vulnerability," spokeswoman said.
"We confirm that the vulnerability has been fixed. In addition, we are investigating recent reports of increased abusive traffic and will work diligently to fix any vulnerabilities that are found."
The spokeswoman encouraged Yahoo users to change their password to a more secure one containing combined letters, numbers and symbols.
The spokeswoman also advised those with a Yahoo account not to click on suspicious links that they receive through email or from other sources.