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https://issues.apache.org/jira/browse/XERCESJ-1759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17761470#comment-17761470
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Elliotte Rusty Harold commented on XERCESJ-1759:
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The first question I'll ask is whether this is quadratic, exponential, or
linear. A 20X increase in memory size from raw file to DOM is not unheard of in
this space by any means.
If you add a closing tag at the end does the memory use suddenly drop?
It's possible you simply discovered that Xerces's DOM just isn't that memory
efficient.
> Parsing xml cannot limit the maximum element depth, resulting in excessive
> memory usage and DOS.
> ------------------------------------------------------------------------------------------------
>
> Key: XERCESJ-1759
> URL: https://issues.apache.org/jira/browse/XERCESJ-1759
> Project: Xerces2-J
> Issue Type: Bug
> Components: JAXP (javax.xml.parsers), JAXP (javax.xml.validation)
> Affects Versions: 2.12.2
> Reporter: shuailingliang
> Priority: Major
> Labels: security
>
> When parsing an xml file similar to the following by calling the
> javax.xml.parsers.DocumentBuilder#parse(java.io.File) method, the elements
> are nested layer by layer and there is no element closing tag. Since the
> depth of elements cannot be verified, the array in
> org.apache.xerces.impl.XMLDocumentFragmentScannerImpl#fElementStack will
> continue to increase the number of QName objects, resulting in excessive
> memory and DOS problems.
>
> <?xml version=”1.0” encoding=”UTF-8” standalone=”no” ?>
> <A a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A
> a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A
> a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”><A a=”1”>…
>
> After testing, we found that a file of 12.93M will cause an OOM exception in
> a service with a maximum heap memory of 250M.
>
> We checked the jdk information and found that we can limit the nesting depth
> of xml elements by setting the system property jdk.xml.maxElementDepth. We
> hope xerces can solve this problem.
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