GUEST OPINION: The Australian Signals Directorate's Australian Cyber Security Centre (ACSC), US Cybersecurity and Infrastructure Security Agency (CISA), and US National Security Agency (NSA) have released a joint cybersecurity advisory warning vendors, designers, and developers of web applications and organisations using web applications about insecure direct object reference (IDOR) vulnerabilities, also known as broken object level authorisation (BOLA) vulnerabilities.