diff --git a/src/WritableResourceStream.php b/src/WritableResourceStream.php
index f43f95c..7e04205 100644
--- a/src/WritableResourceStream.php
+++ b/src/WritableResourceStream.php
@@ -23,8 +23,9 @@ public function __construct($stream, LoopInterface $loop, $writeBufferSoftLimit
             throw new \InvalidArgumentException('First parameter must be a valid stream resource');
         }
 
+        // ensure resource is opened for writing (fopen mode must contain either of "waxc+")
         $meta = stream_get_meta_data($stream);
-        if (isset($meta['mode']) && str_replace(array('b', 't'), '', $meta['mode']) === 'r') {
+        if (isset($meta['mode']) && $meta['mode'] !== '' && strtr($meta['mode'], 'waxc+', '.....') === $meta['mode']) {
             throw new \InvalidArgumentException('Given stream resource is not opened in write mode');
         }
 
diff --git a/tests/DuplexResourceStreamTest.php b/tests/DuplexResourceStreamTest.php
index 9ea43f9..6a57c5d 100644
--- a/tests/DuplexResourceStreamTest.php
+++ b/tests/DuplexResourceStreamTest.php
@@ -19,6 +19,21 @@ public function testConstructor()
         $conn = new DuplexResourceStream($stream, $loop);
     }
 
+    /**
+     * @covers React\Stream\DuplexResourceStream::__construct
+     */
+    public function testConstructorWithExcessiveMode()
+    {
+        // excessive flags are ignored for temp streams, so we have to use a file stream
+        $name = tempnam(sys_get_temp_dir(), 'test');
+        $stream = @fopen($name, 'r+eANYTHING');
+        unlink($name);
+
+        $loop = $this->createLoopMock();
+        $buffer = new DuplexResourceStream($stream, $loop);
+        $buffer->close();
+    }
+
     /**
      * @covers React\Stream\DuplexResourceStream::__construct
      */
@@ -45,6 +60,21 @@ public function testConstructorThrowsExceptionOnWriteOnlyStream()
         new DuplexResourceStream(STDOUT, $loop);
     }
 
+    /**
+     * @covers React\Stream\DuplexResourceStream::__construct
+     * @expectedException InvalidArgumentException
+     */
+    public function testConstructorThrowsExceptionOnWriteOnlyStreamWithExcessiveMode()
+    {
+        // excessive flags are ignored for temp streams, so we have to use a file stream
+        $name = tempnam(sys_get_temp_dir(), 'test');
+        $stream = fopen($name, 'weANYTHING');
+        unlink($name);
+
+        $loop = $this->createLoopMock();
+        new DuplexResourceStream($stream, $loop);
+    }
+
     /**
      * @covers React\Stream\DuplexResourceStream::__construct
      */
diff --git a/tests/ReadableResourceStreamTest.php b/tests/ReadableResourceStreamTest.php
index a6909ba..75afd05 100644
--- a/tests/ReadableResourceStreamTest.php
+++ b/tests/ReadableResourceStreamTest.php
@@ -18,6 +18,21 @@ public function testConstructor()
         new ReadableResourceStream($stream, $loop);
     }
 
+    /**
+     * @covers React\Stream\ReadableResourceStream::__construct
+     */
+    public function testConstructorWithExcessiveMode()
+    {
+        // excessive flags are ignored for temp streams, so we have to use a file stream
+        $name = tempnam(sys_get_temp_dir(), 'test');
+        $stream = @fopen($name, 'r+eANYTHING');
+        unlink($name);
+
+        $loop = $this->createLoopMock();
+        $buffer = new ReadableResourceStream($stream, $loop);
+        $buffer->close();
+    }
+
     /**
      * @covers React\Stream\ReadableResourceStream::__construct
      */
@@ -44,6 +59,21 @@ public function testConstructorThrowsExceptionOnWriteOnlyStream()
         new ReadableResourceStream(STDOUT, $loop);
     }
 
+    /**
+     * @covers React\Stream\ReadableResourceStream::__construct
+     * @expectedException InvalidArgumentException
+     */
+    public function testConstructorThrowsExceptionOnWriteOnlyStreamWithExcessiveMode()
+    {
+        // excessive flags are ignored for temp streams, so we have to use a file stream
+        $name = tempnam(sys_get_temp_dir(), 'test');
+        $stream = fopen($name, 'weANYTHING');
+        unlink($name);
+
+        $loop = $this->createLoopMock();
+        new ReadableResourceStream($stream, $loop);
+    }
+
     /**
      * @covers React\Stream\ReadableResourceStream::__construct
      */
diff --git a/tests/WritableStreamResourceTest.php b/tests/WritableStreamResourceTest.php
index 5f0400e..23da14b 100644
--- a/tests/WritableStreamResourceTest.php
+++ b/tests/WritableStreamResourceTest.php
@@ -19,6 +19,21 @@ public function testConstructor()
         $buffer->on('error', $this->expectCallableNever());
     }
 
+    /**
+     * @covers React\Stream\WritableResourceStream::__construct
+     */
+    public function testConstructorWithExcessiveMode()
+    {
+        // excessive flags are ignored for temp streams, so we have to use a file stream
+        $name = tempnam(sys_get_temp_dir(), 'test');
+        $stream = @fopen($name, 'w+eANYTHING');
+        unlink($name);
+
+        $loop = $this->createLoopMock();
+        $buffer = new WritableResourceStream($stream, $loop);
+        $buffer->close();
+    }
+
     /**
      * @covers React\Stream\WritableResourceStream::__construct
      * @expectedException InvalidArgumentException
@@ -43,6 +58,21 @@ public function testConstructorThrowsExceptionOnReadOnlyStream()
         new WritableResourceStream($stream, $loop);
     }
 
+    /**
+     * @covers React\Stream\WritableResourceStream::__construct
+     * @expectedException InvalidArgumentException
+     */
+    public function testConstructorThrowsExceptionOnReadOnlyStreamWithExcessiveMode()
+    {
+        // excessive flags are ignored for temp streams, so we have to use a file stream
+        $name = tempnam(sys_get_temp_dir(), 'test');
+        $stream = fopen($name, 'reANYTHING');
+        unlink($name);
+
+        $loop = $this->createLoopMock();
+        new WritableResourceStream($stream, $loop);
+    }
+
     /**
      * @covers React\Stream\WritableResourceStream::__construct
      */