Southern Illinois University (SIU) suffered a data breach between May 29–30, 2023, caused by an external system hacking incident. The breach exposed Social Security Numbers (SSNs) of 38,286 individuals, including 10 Maine residents. As a mitigation measure, SIU is providing 12 months of free Experian credit monitoring to affected parties. The compromised data—primarily SSNs—poses a high risk of identity theft, financial fraud, and long-term reputational harm to the institution. The breach underscores vulnerabilities in SIU’s cybersecurity defenses, particularly against external intrusions targeting sensitive personal identifiers. While no immediate financial losses were reported, the exposure of SSNs elevates the potential for downstream fraudulent activities, regulatory scrutiny, and erosion of trust among students, faculty, and alumni. The incident was formally disclosed by the Maine Office of the Attorney General on October 25, 2023, highlighting the delayed public notification timeline.