diff --git a/framework/Pack/lib/Horde/Pack.php b/framework/Pack/lib/Horde/Pack.php
index d7dfcb04660..60f77c97300 100644
--- a/framework/Pack/lib/Horde/Pack.php
+++ b/framework/Pack/lib/Horde/Pack.php
@@ -126,7 +126,11 @@ public function pack($data, array $opts = array())
              *   128 - RESERVED for future use (if set, indicates that initial
              *         byte will extend into next byte).
              * Packed (and compressed data) follows this byte. */
-            $packed = $val->pack($data);
+            try {
+                $packed = $val->pack($data);
+            } catch (Horde_Pack_Exception $e) {
+                continue;
+            }
 
             if ($opts['compress'] !== false) {
                 if ($opts['compress'] === 0) {
diff --git a/framework/Pack/lib/Horde/Pack/Driver/Json.php b/framework/Pack/lib/Horde/Pack/Driver/Json.php
index dc78e26367a..6afb3c9043d 100644
--- a/framework/Pack/lib/Horde/Pack/Driver/Json.php
+++ b/framework/Pack/lib/Horde/Pack/Driver/Json.php
@@ -37,12 +37,17 @@ static public function supported()
      */
     public function pack($data)
     {
+        $d = json_encode($data);
+        if (json_last_error() === 5) {
+            throw new Horde_Pack_Exception('Non UTF-8 data cannot be JSON packed.');
+        }
+
         /* For JSON, we need to keep track whether the initial data was
          * an object or class. The initial JSON character is one of the
          * following:
          *   0: Non-array
          *   1: Array */
-        return intval(is_array($data)) . json_encode($data);
+        return intval(is_array($data)) . $d;
     }
 
     /**
diff --git a/framework/Pack/package.xml b/framework/Pack/package.xml
index dfa0a981ea3..1f2efc0e38b 100644
--- a/framework/Pack/package.xml
+++ b/framework/Pack/package.xml
@@ -21,7 +21,7 @@
  </stability>
  <license uri="http://www.horde.org/licenses/lgpl21">LGPL-2.1</license>
  <notes>
-* 
+* [mms] Don&apos;t use JSON driver to pack if input contains non-UTF8 data (Bug #13275).
  </notes>
  <contents>
   <dir baseinstalldir="/" name="/">
@@ -182,7 +182,7 @@
    <date>2014-04-03</date>
    <license uri="http://www.horde.org/licenses/lgpl21">LGPL-2.1</license>
    <notes>
-* 
+* [mms] Don&apos;t use JSON driver to pack if input contains non-UTF8 data (Bug #13275).
    </notes>
   </release>
  </changelog>
diff --git a/framework/Pack/test/Horde/Pack/PackTest.php b/framework/Pack/test/Horde/Pack/PackTest.php
index 65d6d167432..be0f2391bc5 100644
--- a/framework/Pack/test/Horde/Pack/PackTest.php
+++ b/framework/Pack/test/Horde/Pack/PackTest.php
@@ -34,4 +34,25 @@ public function testExpectedExceptionOnSerialize()
         serialize($pack);
     }
 
+    // Bug #13275
+    public function testNonUtf8Pack()
+    {
+        // ISO-8859-1 string
+        $data = base64_decode('VORzdA==');
+
+        $pack = new Horde_Pack();
+
+        $p = $pack->pack($data, array(
+            'drivers' => array(
+                'Horde_Pack_Driver_Json',
+                'Horde_Pack_Driver_Serialize'
+            )
+        ));
+
+        $this->assertEquals(
+            $data,
+            $pack->unpack($p)
+        );
+    }
+
 }