Comment 10 for bug 1838370

Here is a quick reproducer.

sudo apt update
sudo apt install slapd ldap-utils -y

Reconfigure the slapd package. When asked about a domain, use "example.com". Choose a password, and accept defaults for everything else:

sudo dpkg-reconfigure slapd

Create a file called add-rwm.ldif with these contents:
dn: cn=module{0},cn=config
changetype: modify
add: olcModuleLoad
olcModuleLoad: rwm

dn: olcOverlay=rwm,olcDatabase={1}mdb,cn=config
changetype: add
objectClass: olcOverlayConfig
objectClass: olcRwmConfig
olcOverlay: rwm
olcRwmRewrite: {0} rwm-rewriteEngine "on"
olcRwmRewrite: {1} rwm-rewriteContext "searchFilter"
olcRwmRewrite: {2} rwm-rewriteRule "(.*)(uid=root)(.*)" "$1$2$3" "#"

Then run:
sudo ldapadd -Q -Y EXTERNAL -H ldapi:/// -f add-rwm.ldif

And then, to trigger the crash:
ldapsearch -x -h localhost -b dc=example,dc=com -LLL uid=root

slapd will die, and /var/crash will have a crash file for slapd.