HackingFinancial ServicesFinanceStolen CredentialsCustomer Data InvolvedTargetedIdentity (basic)Government IDFinancial accountMediumContained

Topstep LLC

bd_9075a6acb8fc2654 · schema v1 · pii pii-v2

Severity

Medium

Discovered

Dec 15, 2025

Filed

Jan 15, 2026

To disclose

—

Affected

Not disclosed

Confidence

66%

Full breach record for Topstep LLC →2 incidents on file

Topstep LLC notified affected individuals of a cybersecurity incident discovered on December 15, 2025. Cyber threat actors used credential stuffing with stolen credentials from external sources to gain unauthorized access to user accounts. The incident potentially exposed names, contact info, dates of birth, government IDs, tax info, and SSNs. Topstep blocked malicious IPs, forced password resets, and is implementing mandatory MFA. Affected individuals were offered complimentary Experian IdentityWorks.

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Incident timeline

undetected · 1 days

Dec 14, 2025

Begins

Dec 15, 2025

Discovered

Jan 15, 2026

Filed

Tracked as a single-filing incident — the only disclosure on record for this event so far.ConfirmedView incident

Name: Topstep LLC
norm: topstep
Domain: topstep.com

Name: Topstep LLC
norm: topstep
Domain: topstep.com
Industry: Financial Servicesllm

Discovered: Dec 15, 2025
Breach occurred: Dec 14, 2025
Undetected for: 1 dayoccurrence → discovery
Materiality determined: —
Notification sent: Jan 15, 2026
Affected individuals: Not disclosed
Data types: Identity (basic)Government IDFinancial account
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1566.002 Spearphishing Link
Threat actor: ExternalFinancial
Initial access: valid_credentials

During the incident: IP addresses identified as sending high volumes of traffic were immediately blocked at the Web Application Firewall (WAF) and ALB level
Forced a password reset for all potentially affected accounts, specifically prohibiting the re-use of old passwords
Working to implement additional security features to its login processes to assist data subjects protect their information, such as mandatory multifactor authentication
Changes made: Working to implement additional security features to its login processes to assist data subjects protect their information, such as mandatory multifactor authentication
Source: Quoted from the filing itself, not independently verified.

Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

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.

Source URL: https://nebraska.gov/ago/data-breach/documents/7f38b3c8-e2db-4d43-b692-83af24799949.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jan 15, 2026
Raw hash: 902e69e779bbef86b18f193fd675e5b98b5a256fda547c879217bccad9389dcc

Reporting entityTopstep LLC

Victim entityTopstep LLC

Incidentdiscovered Dec 15, 2025

Stated responseIP addresses identified as sending high volumes of traffic were immediately blocked at the Web Application Firewall (WAF) and ALB level

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancenebraska.gov