Recent updates to IE contain a serious regression that leaves systems once more vulnerable to a flaw fixed more than two years ago, according to security researchers.

The vulnerability, which involves how IE processes XML files, gives rise to information disclosure risks. The security bug was patched and closed back in Aug 2002, six months after Microsoft was initially notified about it by Israeli firm GreyMagic Software, which discovered the problem. Microsoft rated the vulnerability as "moderate" when it fixed the flaw as part a cumulative update (MS02-047) to IE issued on August 22 2002.

That should have been the end of it but the bug resurfaced again late last week, when veteran browser bug hunter Georgi Guninski retested the issue and found the patch is no longer applicable. GreyMagic Software has confirmed Guninski's tests. It said IE is still vulnerable despite a cumulative fix to IE issued earlier this week along with nine other security updates in the latest monthly patch batch from Microsoft. ®

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