Southern Illinois University Data Breach Exposes Personal Information of Over 1,600 Individuals Southern Illinois University (SIU), a public multi-campus system in Illinois, disclosed a data breach that occurred between July 10 and August 16, 2025, after an unauthorized user accessed sensitive files. The university did not detect the incident until July 24, 2026, nearly a year later. The breach exposed personal data, including names, addresses, and Social Security numbers, affecting 1,597 Texas residents and 23 Vermont residents. The incident was also reported to the California Attorney General, and affected individuals were notified via U.S. Mail. In response, SIU established a toll-free response line for inquiries, available Monday through Friday (8 a.m.–11 p.m.) and Saturday (9 a.m.–6 p.m.), excluding holidays. The university is also offering credit monitoring services to impacted individuals, with enrollment details provided in notification letters.

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.