diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 8dc48b347f..9a7bfcd9b5 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -5,6 +5,10 @@
 
 2016-12-05  Nick Clifton  <nickc@redhat.com>
 
+	PR binutils/20905
+	* peicode.h (pe_ILF_object_p): Use strnlen to avoid running over
+	the end of the string buffer.
+
 	PR binutils/20907
 	* peicode.h (pe_ILF_build_a_bfd): Replace abort with error return.
 
diff --git a/bfd/peicode.h b/bfd/peicode.h
index ee47a67797..5d55711293 100644
--- a/bfd/peicode.h
+++ b/bfd/peicode.h
@@ -1269,7 +1269,8 @@ pe_ILF_object_p (bfd * abfd)
     }
 
   symbol_name = (char *) ptr;
-  source_dll  = symbol_name + strlen (symbol_name) + 1;
+  /* See PR 20905 for an example of where the strnlen is necessary.  */
+  source_dll  = symbol_name + strnlen (symbol_name, size - 1) + 1;
 
   /* Verify that the strings are null terminated.  */
   if (ptr[size - 1] != 0