diff --git a/pkgs/development/libraries/expat/CVE-2015-1283.patch b/pkgs/development/libraries/expat/CVE-2015-1283.patch
deleted file mode 100644
index 33b975912d40..000000000000
--- a/pkgs/development/libraries/expat/CVE-2015-1283.patch
+++ /dev/null
@@ -1,77 +0,0 @@
-Found at https://hg.mozilla.org/releases/mozilla-esr31/rev/2f3e78643f5c on 2015-07-27.  Modified: replaced path parser/expat/lib/xmlparse.c with lib/xmlparse.c.
-diff --git a/lib/xmlparse.c b/lib/xmlparse.c
---- a/lib/xmlparse.c
-+++ b/lib/xmlparse.c
-@@ -1646,29 +1646,40 @@ XML_ParseBuffer(XML_Parser parser, int l
-   XmlUpdatePosition(encoding, positionPtr, bufferPtr, &position);
-   positionPtr = bufferPtr;
-   return result;
- }
- 
- void * XMLCALL
- XML_GetBuffer(XML_Parser parser, int len)
- {
-+/* BEGIN MOZILLA CHANGE (sanity check len) */
-+  if (len < 0) {
-+    errorCode = XML_ERROR_NO_MEMORY;
-+    return NULL;
-+  }
-+/* END MOZILLA CHANGE */
-   switch (ps_parsing) {
-   case XML_SUSPENDED:
-     errorCode = XML_ERROR_SUSPENDED;
-     return NULL;
-   case XML_FINISHED:
-     errorCode = XML_ERROR_FINISHED;
-     return NULL;
-   default: ;
-   }
- 
-   if (len > bufferLim - bufferEnd) {
--    /* FIXME avoid integer overflow */
-     int neededSize = len + (int)(bufferEnd - bufferPtr);
-+/* BEGIN MOZILLA CHANGE (sanity check neededSize) */
-+    if (neededSize < 0) {
-+      errorCode = XML_ERROR_NO_MEMORY;
-+      return NULL;
-+    }
-+/* END MOZILLA CHANGE */
- #ifdef XML_CONTEXT_BYTES
-     int keep = (int)(bufferPtr - buffer);
- 
-     if (keep > XML_CONTEXT_BYTES)
-       keep = XML_CONTEXT_BYTES;
-     neededSize += keep;
- #endif  /* defined XML_CONTEXT_BYTES */
-     if (neededSize  <= bufferLim - buffer) {
-@@ -1687,17 +1698,25 @@ XML_GetBuffer(XML_Parser parser, int len
-     }
-     else {
-       char *newBuf;
-       int bufferSize = (int)(bufferLim - bufferPtr);
-       if (bufferSize == 0)
-         bufferSize = INIT_BUFFER_SIZE;
-       do {
-         bufferSize *= 2;
--      } while (bufferSize < neededSize);
-+/* BEGIN MOZILLA CHANGE (prevent infinite loop on overflow) */
-+      } while (bufferSize < neededSize && bufferSize > 0);
-+/* END MOZILLA CHANGE */
-+/* BEGIN MOZILLA CHANGE (sanity check bufferSize) */
-+      if (bufferSize <= 0) {
-+        errorCode = XML_ERROR_NO_MEMORY;
-+        return NULL;
-+      }
-+/* END MOZILLA CHANGE */
-       newBuf = (char *)MALLOC(bufferSize);
-       if (newBuf == 0) {
-         errorCode = XML_ERROR_NO_MEMORY;
-         return NULL;
-       }
-       bufferLim = newBuf + bufferSize;
- #ifdef XML_CONTEXT_BYTES
-       if (bufferPtr) {
-
-
-
-
diff --git a/pkgs/development/libraries/expat/default.nix b/pkgs/development/libraries/expat/default.nix
index 774190278cb3..bc1801ef804f 100644
--- a/pkgs/development/libraries/expat/default.nix
+++ b/pkgs/development/libraries/expat/default.nix
@@ -1,15 +1,13 @@
 { stdenv, fetchurl }:
 
 stdenv.mkDerivation rec {
-  name = "expat-2.1.0";
+  name = "expat-2.1.1";
 
   src = fetchurl {
-    url = "mirror://sourceforge/expat/${name}.tar.gz";
-    sha256 = "11pblz61zyxh68s5pdcbhc30ha1b2vfjd83aiwfg4vc15x3hadw2";
+    url = "mirror://sourceforge/expat/${name}.tar.bz2";
+    sha256 = "0ryyjgvy7jq0qb7a9mhc1giy3bzn56aiwrs8dpydqngplbjq9xdg";
   };
 
-  patches = [ ./CVE-2015-1283.patch ];
-
   outputs = [ "dev" "out" ]; # TODO: fix referrers
   outputBin = "dev";
 
@@ -17,6 +15,8 @@ stdenv.mkDerivation rec {
 
   outputMan = "dev"; # tiny page for a dev tool
 
+  doCheck = true;
+
   meta = with stdenv.lib; {
     homepage = http://www.libexpat.org/;
     description = "A stream-oriented XML parser library written in C";