Attackers are exploiting an unpatched bug in Adobe System's popular Flash Player, security researchers warned Tuesday.
The bug, which is in the most up-to-date version of Flash, was reported by researchers at the SAN Institute's Internet Storm Center and by others from Symantec.
"Adobe Flash Player is prone to an unspecified remote code-execution vulnerability," Symantec said in a warning posted to its SecurityFocus site. "An attacker may exploit this issue to execute arbitrary code in the context of the affected application. Failed exploit attempts will likely result in denial-of-service conditions.
"Symantec has observed that this issue is being actively exploited in the wild," the company added.
The last serious Flash vulnerability fixed by Adobe was patched last month. That bug was used in late March by a hacker to take down a laptop running Windows Vista and claim a US$5,000 prize in a contest sponsored by 3Com's TippingPoint security company.
According to Symantec, Flash Player 188.8.131.52 -- the version currently available for download from the Adobe site -- is vulnerable to attack. Flash is used by a huge number of Web sites, including YouTube, to display multimedia content.
Adobe officials were not immediately available for comment.