Mercari Marketplace Alert! 2021 Data Hack and Breach. Proactive Steps You Should Take.

 Mercari Alert! It has been confirmed that the Mercari Marketplace was hacked and compromised at the beginning of 2021.

At the end of May 2021, Mercari quietly released to the public, that it's marketplace had been compromised with thousands of confidential, financial, and personal information being exposed.

What hasn't been clear from the publicly available information is whether this breach applied only to Mercari Japan marketplace, Mercari US marketplace or both marketplaces.  Other than issuing a rather vague notification and promise to do better, along with basic information about the type of hack that breached their security measures, there isn't much more information available.

Watch the Mercari Alert 2021 Data Breach update on Utreon.

Bleeping Computer, a website that is popular for its rich software archive of free anti-virus, firewall software and similar computer security software was one of the first to have any details about the breach. You can view that article on Bleeping Computer




Mercari released the following graphics detailing how the Codecov breach and compromise occurred, but unless you are a tech person, they probably do not make a whole lot of sense for you, and in that case, your most important goal should is to take proactive steps to secure your own account, if you use Mercari.

 Mercari drops Codecov

At the conclusion of their internal investigation, Mercari did what any responsible company would do, and removed the Codecov functions from its website, app and system.


The company says it had to wait on disclosing the data breach until the end of May 2021, because its investigation activities had been ongoing. They also wanted to make sure that any other security weaknesses could be completely identified and remediated to prevent the risk of suffering further attacks and damage.

Mercari has now concluded its investigation and hence come forward with the detailed disclosure in a prepared statement, originally released only in Japanese.



Randy Dreammaker of SellerThink was unable to find any reference to the breach on the US Mercari Marketplaces blog, website, help information or other related Mercari resources of information, so as discussed in the Mercari Alert 2021 Data Breach video on YouTube, Shoppers and sellers on US Mercari can only take proactive steps and assume that their information may have been exposed.  Even if the data breach and hack eventually is confirmed to have only impacted the Mercari Marketplace in Japan, changing you password, e-mail, updating you information, notifying your credit card company and bank that your account may have been exposed in a breach exposing you to identity theft, is just a good practice.


Video in Spanish for Mercari USA users.

Violación de datos de Mercari Marketplace

Mercari anunció que las cuentas de los clientes se filtraron durante un compromiso de varios meses y su seguridad fue pirateada a través de un ataque a la cadena de suministro de Codecov. Randy Dreammaker analiza los detalles relacionados con la violación de datos y los pasos a seguir para proteger la cuenta.