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Sendai City
Sendai, Japan1 source
Confirmed:Confirmed by the organisation, a regulator or a securities filing. First reported 6 Nov 2026.
Sendai City data leak involves 12,211 email addresses
Sendai City disclosed that 12,211 registered email addresses may have been leaked via the TKC/Arara Message My Number card booking system. The disclosure occurred on November 6.
- Type
- Data breach
- Sector
- Government
- Records
- 12.2K records confirmed
- First reported
- 6 Nov 2026
- Latest source
- 6 Nov 2026
What to do
- If you have an account, change that password, and anywhere you reused it.
- Turn on two-factor authentication, ideally an authenticator app or passkey, not SMS.
- Expect phishing that uses your real details. Do not click links in messages about this incident; go to the company's site directly.
- If payment cards were involved, watch statements and ask your bank for a new card.
- If government ID or social security numbers were involved, consider a credit freeze.
- If this is a vendor of yours, ask what of your data they held and whether it was in scope.
- Reset any API keys, SSO trusts or shared credentials you have with them.
- Brief your help desk: attackers often impersonate the breached brand next.
Not sure? Ask an assistant with the sources attached, or have a coding agent check your systems.
Check your systems for Sendai City
Sources
1Confidence 70% that this is real and correctly placed. Locations are city centroids at best. Spotted an error? Report a correction.