psql crashes found when executing slash commands

Hi,

We recently upgraded to Postgres 9.6.8 version.
After the upgrade we are encountering crash for psql and it is happening only when we are executing "slash" commands.

Example:
template1=# create database tempora;
CREATE DATABASE
template1=# \c tempora
Segmentation fault (core dumped)

template1=# create table tmp (emp int);
CREATE TABLE
template1=# select count(*) from tmp;
count
-------
0
(1 row)

template1=# \l
Segmentation fault (core dumped)

Below is the backtrace:
(gdb) bt
#0 0x0000000120037a6c in slash_yylex ()
#1 0x0000000120038d04 in psql_scan_slash_command ()
Backtrace stopped: frame did not save the PC
(gdb) bt full
#0 0x0000000120037a6c in slash_yylex ()
No symbol table info available.
#1 0x0000000120038d04 in psql_scan_slash_command ()
No symbol table info available.
Backtrace stopped: frame did not save the PC

Regards,
Sandhya