Common Vulnerabilities and Exposures assigned an identifier CVE-2010-1916 to
the following vulnerability:

Name: CVE-2010-1916
URL: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-1916
Assigned: 20100511
Reference: MISC: http://www.php-security.org/2010/05/10/mops-2010-019-serendipity-wysiwyg-editor-plugin-configuration-injection-vulnerability/index.html
Reference: MISC: http://www.php-security.org/2010/05/10/mops-2010-020-xinha-wysiwyg-plugin-configuration-injection-vulnerability/index.html

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.

The upstream bug report [1] has links to patches to correct this issue.

[1] http://trac.xinha.org/ticket/1518