The message is "an invitation" from bin Laden, who is in hiding, to listeners to participate in a "jihad to stop the aggression against Gaza," the cable news broadcaster reported Wednesday.
The message was on an Islamist Web site known for posting bin Laden's statements, CNN said, adding it couldn't independently confirm the authenticity of the message. The voice, however, was similar to other recordings bin Laden made.
Bin Laden's last audio message was in mid-May, coinciding with Israel's 60th anniversary, in which he urged followers to liberate Palestine.
Israel began a military operation in Hamas-controlled Gaza on Dec. 27, saying it wanted to halt the firing of rockets from the Gaza Strip onto targets in Israel.