diff --git a/libvoikko-2.3.1-handle-embedded-null-input.patch b/libvoikko-2.3.1-handle-embedded-null-input.patch
new file mode 100644
index 0000000..29a1dea
--- /dev/null
+++ b/libvoikko-2.3.1-handle-embedded-null-input.patch
@@ -0,0 +1,83 @@
+diff -ur libvoikko-2.3.1.orig/python/libvoikko.py libvoikko-2.3.1/python/libvoikko.py
+--- libvoikko-2.3.1.orig/python/libvoikko.py	2011-06-12 20:15:54.375366677 +0300
++++ libvoikko-2.3.1/python/libvoikko.py	2011-06-12 20:34:29.599151476 +0300
+@@ -261,6 +261,9 @@
+ 			if error != None:
+ 				raise VoikkoException(u"Initialization of Voikko failed: " + unicode(error, "UTF-8"))
+ 	
++	def __isValidInput(self, text):
++		return u"\0" not in text
++
+ 	def terminate(self):
+ 		"""Uninitialize this Voikko instance. The instance must be initialized again
+ 		before it can be used.
+@@ -291,6 +294,9 @@
+ 		"""Check the spelling of given word. Return true if the word is correct,
+ 		false if it is incorrect.
+ 		"""
++		if not self.__isValidInput(word):
++			return False
++
+ 		_checkInited(self)
+ 		result = self.lib.voikko_spell_ucs4(self.handle, word)
+ 		if result == 0:
+@@ -304,6 +310,9 @@
+ 		"""Generate a list of suggested spellings for given (misspelled) word.
+ 		If the given word is correct, the list contains only the word itself.
+ 		"""
++		if not self.__isValidInput(word):
++			return []
++
+ 		_checkInited(self)
+ 		# FIXME: This should be done directly within libvoikko
+ 		if self.spell(word):
+@@ -344,6 +353,9 @@
+ 		Unlike the C based API this method accepts multiple paragraps
+ 		separated by newline characters.
+ 		"""
++		if not self.__isValidInput(text):
++			return []
++
+ 		_checkInited(self)
+ 		textUnicode = unicode(text)
+ 		errorList = []
+@@ -365,6 +377,9 @@
+ 		analysis results. The results are represented as maps having property
+ 		names as keys and property values as values.
+ 		"""
++		if not self.__isValidInput(word):
++			return []
++
+ 		_checkInited(self)
+ 		cAnalysisList = self.lib.voikko_analyze_word_ucs4(self.handle, word)
+ 		pAnalysisList = []
+@@ -392,6 +407,19 @@
+ 	def tokens(self, text):
+ 		"""Split the given natural language text into a list of Token objects."""
+ 		_checkInited(self)
++		startIndex = 0
++		tokens = []
++		while True:
++			i = text.find(u"\0", startIndex)
++			if i == -1:
++				break
++			tokens = tokens + self.__splitTokens(text[startIndex:i])
++			tokens.append(Token(u"\0", Token.UNKNOWN))
++			startIndex = i + 1
++		tokens = tokens + self.__splitTokens(text[startIndex:])
++		return tokens
++	
++	def __splitTokens(self, text):
+ 		uniText = unicode(text)
+ 		result = []
+ 		textLen = len(uniText)
+@@ -416,6 +444,9 @@
+ 		  '=' = hyphentation point (character at this position
+ 		        is replaced by the hyphen.)
+ 		"""
++		if not self.__isValidInput(word):
++			return "".ljust(len(word))
++
+ 		_checkInited(self)
+ 		cHyphenationPattern = self.lib.voikko_hyphenate_ucs4(self.handle, word)
+ 		hyphenationPattern = string_at(cHyphenationPattern)
diff --git a/libvoikko.spec b/libvoikko.spec
index c56e084..3c8b0f4 100644
--- a/libvoikko.spec
+++ b/libvoikko.spec
@@ -1,7 +1,7 @@
 %{!?python_sitelib: %global python_sitelib %(%{__python} -c "from distutils.sysconfig import get_python_lib; print get_python_lib()")}
 Name:           libvoikko
 Version:        2.3.1
-Release:        1%{?dist}
+Release:        2%{?dist}
 Summary:        Voikko is a library for spellcheckers and hyphenators
 
 Group:          System Environment/Libraries
@@ -11,6 +11,8 @@ URL:            http://voikko.sourceforge.net/
 Source0:        http://downloads.sourceforge.net/voikko/%{name}-%{version}.tar.gz
 # The usual format of test release URLs
 #Source0:        http://www.puimula.org/htp/testing/%{name}-%{version}rc1.tar.gz
+Patch0:         %{name}-%{version}-handle-embedded-null-input.patch
+
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 BuildRequires:  python-devel
@@ -63,6 +65,7 @@ tasks on Finnish text.
 
 %prep
 %setup -q
+%patch0 -p1
 
 
 %build
@@ -121,6 +124,11 @@ rm -rf $RPM_BUILD_ROOT
 %{python_sitelib}/%{name}.py*
 
 %changelog
+* Sun Jun 12 2011 Ville-Pekka Vainio <vpivaini AT cs.helsinki.fi> - 2.3.1-2
+- Backport a security update from 3.2.1: fix handling of embedded null
+  characters in input strings entered through the Python interface.
+
+
 * Thu Feb 18 2010 Ville-Pekka Vainio <vpivaini AT cs.helsinki.fi> - 2.3.1-1
 - Version 2.3.1 contains fixes for bugs found in version 2.3