The dynamic configuration feature in Xinha WYSIWYG editor 0.96 Beta 2 and earlier, as used in Serendipity 1.5.2 and earlier, allows remote attackers to bypass intended access restrictions and modify the configuration of arbitrary plugins via (1) crafted backend_config_secret_key_location and backend_config_hash parameters that are used in a SHA1 hash of a shared secret that can be known or externally influenced, which are not properly handled by the "Deprecated config passing" feature; or (2) crafted backend_data and backend_data[key_location] variables, which are not properly handled by the xinha_read_passed_data function. NOTE: this can be leveraged to upload and possibly execute arbitrary files via config.inc.php in the ImageManager plugin.
https://bugzilla.redhat.com/show_bug.cgi?id=591701
http://www.vupen.com/english/advisories/2010/1401
http://www.securityfocus.com/bid/40033
http://trac.xinha.org/ticket/1518
http://secunia.com/advisories/40124
http://secunia.com/advisories/39782
http://lists.fedoraproject.org/pipermail/package-announce/2010-June/042577.html