diff --git a/ChangeLog b/ChangeLog
index ce4786a3c..72336fe10 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2018-01-26  Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Source/GSFTPURLHandle.m: change memcpy to memmove to avoid possible
+	problems with overlapping source and destination areas.
+
 2018-02-01  Fred Kiefer <fredkiefer@gmx.de>
 
 	* Source/GSFormat.m: Call va_end with the correct parameter.
diff --git a/Source/GSFTPURLHandle.m b/Source/GSFTPURLHandle.m
index f374ab9ac..f91d0210a 100644
--- a/Source/GSFTPURLHandle.m
+++ b/Source/GSFTPURLHandle.m
@@ -321,7 +321,7 @@ NSString * const GSTelnetTextKey = @"GSTelnetTextKey";
 			  len -= 3;
 			  if (len - i > 0)
 			    {
-			      memcpy(ptr, &ptr[3], len - i);
+			      memmove(ptr, &ptr[3], len - i);
 			    }
 			  i--;			// Try again.
 			}
@@ -336,7 +336,7 @@ NSString * const GSTelnetTextKey = @"GSTelnetTextKey";
 		      len--;
 		      if (len - i > 0)
 			{
-			  memcpy(ptr, &ptr[1], len - i);
+			  memmove(ptr, &ptr[1], len - i);
 			}
 		    }
 		  else
@@ -348,7 +348,7 @@ NSString * const GSTelnetTextKey = @"GSTelnetTextKey";
 		      len -= 2;
 		      if (len - i > 0)
 			{
-			  memcpy(ptr, &ptr[2], len - i);
+			  memmove(ptr, &ptr[2], len - i);
 			}
 		      i--;	// Try again from here.
 		    }
@@ -418,7 +418,7 @@ NSString * const GSTelnetTextKey = @"GSTelnetTextKey";
 	      pos -= s;
 	      if (len > 0)
 		{
-		  memcpy(ptr, &ptr[s], len);
+		  memmove(ptr, &ptr[s], len);
 		}
 	    }
 	  [ibuf setLength: len];