diff --git a/mysql-test/r/parser.result b/mysql-test/r/parser.result
index 25143f97d9a..9a14c0e324b 100644
--- a/mysql-test/r/parser.result
+++ b/mysql-test/r/parser.result
@@ -663,3 +663,12 @@ select 1<<!0, 1 << !0;
 select 0<!0,  0 < ! 0;
 0<!0	0 < ! 0
 1	1
+#
+# MDEV-11171 Assertion `m_cpp_buf <= ptr && ptr <= m_cpp_buf + m_buf_length' failed in Lex_input_stream::body_utf8_append(const char*, const char*)
+#
+CREATE TABLE t1 (id INT);
+CREATE TRIGGER tr AFTER DELETE ON t1 FOR EACH ROW SET @a = 1\;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '\' at line 1
+PREPARE stmt FROM 'CREATE TRIGGER tr AFTER DELETE ON t1 FOR EACH ROW SET @a = 1\\';
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '\' at line 1
+DROP TABLE t1;
diff --git a/mysql-test/t/parser.test b/mysql-test/t/parser.test
index c6aa8927848..1e3458eafdf 100644
--- a/mysql-test/t/parser.test
+++ b/mysql-test/t/parser.test
@@ -770,3 +770,13 @@ select 2>!0,  2 > ! 0;
 select 0<=!0, 0 <= !0;
 select 1<<!0, 1 << !0;
 select 0<!0,  0 < ! 0;
+
+--echo #
+--echo # MDEV-11171 Assertion `m_cpp_buf <= ptr && ptr <= m_cpp_buf + m_buf_length' failed in Lex_input_stream::body_utf8_append(const char*, const char*)
+--echo #
+CREATE TABLE t1 (id INT);
+--error ER_PARSE_ERROR
+CREATE TRIGGER tr AFTER DELETE ON t1 FOR EACH ROW SET @a = 1\;
+--error ER_PARSE_ERROR
+PREPARE stmt FROM 'CREATE TRIGGER tr AFTER DELETE ON t1 FOR EACH ROW SET @a = 1\\';
+DROP TABLE t1;
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index ee0e09acbf9..2462f0fea17 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -1074,7 +1074,7 @@ static int lex_one_token(YYSTYPE *yylval, THD *thd)
       state= (enum my_lex_states) state_map[c];
       break;
     case MY_LEX_ESCAPE:
-      if (lip->yyGet() == 'N')
+      if (!lip->eof() && lip->yyGet() == 'N')
       {					// Allow \N as shortcut for NULL
 	yylval->lex_str.str=(char*) "\\N";
 	yylval->lex_str.length=2;