WebCore in Apple Mac OS X 10.3.9 and 10.4 through 10.4.7 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via crafted HTML that triggers a "memory management error" in WebKit, possibly due to a buffer overflow, as originally reported for the KHTMLParser::popOneBlock function in Apple Safari 2.0.4 using Javascript that changes document.body.innerHTML within a DIV tag.