diff --git a/src/internal.c b/src/internal.c
index 41dec3f..2a49070 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -1404,6 +1404,15 @@ static int GetInputText(WOLFSSH* ssh, byte** pEol)
 
         eol = WSTRNSTR((const char*)ssh->inputBuffer.buffer, "\r\n",
                        ssh->inputBuffer.length);
+#ifndef WOLFSSH_STRICT_PROTOCOL_EXCHANGE
+        /* section 4.2 in RFC 4253 states that can be lenient on the CR for
+         * interop with older or undocumented versions of SSH */
+        if (!eol) {
+            WLOG(WS_LOG_DEBUG, "Checking for older version of protocol exchange");
+            eol = WSTRNSTR((const char*)ssh->inputBuffer.buffer, "\n",
+                       ssh->inputBuffer.length);
+        }
+#endif
 
         if (eol)
             gotLine = 1;