DisclosureLens
HackingEducationMedium

Chester County Library System, PA

bd_19412a253040ab1e · schema v1 · pii pii-v1

Severity

Medium

Discovered

Oct 17, 2025

Filed

Oct 28, 2025

To disclose

11 days

Affected · nationwide

1,2811 in this filing

Confidence

55%
Full breach record for Chester County Library System, PA2 incidents on file

Chester County Library System experienced a data breach due to an external system breach (hacking) affecting 1281 individuals, including 1 Maine resident.

Maine clockDiscovered Oct 17, 2025Filed with AG Oct 28, 202511d ME AG ≤30d11 days discovery → filing
AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.

Incident timeline

undetected · 34 days
discovery → filing · 11 days

Sep 13, 2025

Begins

Oct 17, 2025

Discovered

Oct 28, 2025

Filed

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed1,281 affectedView incident

Evidence ladder

Leak-site claim

Attacker assertion only. Establishes: claim date, group, alleged victim.

Press / market report

Unlocks: incident narrative, operational impact. Still no compliance clock.

State AG / regulator filingThis record

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statement

Unlocks: materiality, stated response, full audit trail. Ceiling removed.