From the changelog:
SMF 1.1.13 8 February 2011
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February 2011
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! Validate odd URLs (QueryString, Subs.php)
January 2011
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! Search was returning incorrect results (Search.php) (thank you ioszilla!)
! Reserve HTML for admin only in news. (ManageNews.php, backported from 2.0, thank you Ghost!)
! SSI.php did not handle guest access correctly for forums having guest access disabled. (SSI.php, ssi_examples.php) (backported from 2.0)
& Update news section message for the current behavior. (Admin language file)