(The fix and CVE number for this issue are not known)
A specially crafted web-page can trigger a use-after-free vulnerability in Microsoft Internet Explorer 9. The use appears to happen only once almost immediately after the free, which makes practical exploitation unlikely.
Microsoft Internet Explorer 9
It appears there is an implementation bug in the
splitText method of
CDATASection (Text) objects in SVG.
splitText should split a
Text nodes, by creating a new
Text node and moving some of the
text data from the original node to the new node. After this, each node
contains a sub-string of the original text.
The bug can be triggered by calling this method with zero as the index argument
CDATASection which contains some text. In this case, the code will
return a new
Text node that contains the entire text but it does not remove
the text from the original node. I am speculating that this causes an
additional reference to the test data without increasing its reference counter.
This failure to increase the reference counter can cause this reference counter
to drop to zero before all references are destroyed. I believe this is the case
because the below repro triggers a use-after-free.
I've created another, more complex repro as well:Repro.
This report was generated using a predecessor of BugId, a Python script created to detect, analyze and id application bugs. Don't waste time manually analyzing issues and writing reports but try BugId out yourself today! You'll get even better reports than this one with the current version.id: MSHTML.
dll!CMarkupPointer:: MoveToGap Arbitrary AVR(76D515D4) description: Security: Attempt to read from unallocated arbitrary memory (@0x0B4DEFF0) in MSHTML. dll!CMarkupPointer:: MoveToGap note: Based on this information, this is expected to be a security issue! application: MSIE 9. 00. 8112. 16421