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.
The XSL stylesheet implementation in WebKit in Apple Safari before 4.0, iPhone OS 1.0 through 2.2.1, and iPhone OS for iPod touch 1.1 through 2.2.1 does not properly handle XML external entities, which allows remote attackers to read arbitrary files via a crafted DTD, as demonstrated by a file:///etc/passwd URL in an entity declaration, related to an "XXE attack."