Symantec has reported <A HREF="http://news.zdnet.com/2100-1009_22-5646871.html?tag=zdnn.alert">glitches in its antivirus software</A> that could allow hackers to launch denial-of-service attacks on computers running the applications. In a notice posted on its Web site this week, Symantec detailed two similar vulnerabilities found in its Norton AntiVirus software, which is sold on its own or bundled in Norton Internet Security and Norton System Works. The flaws, which could lead to computers crashing or slowing severely if attacked, are limited to versions of the software released for 2004 and 2005.