Snapchat users were greeted with an alarming change to Snap Maps this morning: New York City had been renamed “Jewtropolis.”

Even worse, social media was filled reports of maps on other websites and services with the same change, including Zillow, The Weather Channel, Citibike, and Streeteasy.

Whatever mapping service that Snapchat, CitiBike, StreetEasy, (perhaps others) use — it seems — is showing New York City as "Jewtropolis" this morning. pic.twitter.com/nsVe8goLyo — Micah Grimes (@MicahGrimes) August 30, 2018

Couldn't find a way to report directly to @streeteasy or @zillow or @openstreetmap so here's a screen shot of a condo located in "Jewtropolis". Assuming they've been hacked. Might want to get on that and fix it. #Antisemitic @ADL_National pic.twitter.com/Z36GdrzLo9 — Brian P. Klein (@brianpklein) August 30, 2018

The anti-Semitic vandalism made its way across the internet so quickly because all these websites and apps depend on a third party for their mapping data.

Hey Dan! Thanks for bringing this to our attention. Snap Map relies on third party mapping data which has unfortunately been subject to vandalism. We are working with our partner Mapbox to get this fixed immediately. — Snapchat Support (@snapchatsupport) August 30, 2018

Founded in 2010, Mapbox is a mapping and geolocation data startup that provides services to companies such as Foursquare, Evernote, and the previously mentioned sites and apps. To do this without the resources of a larger company like Google, Mapbox feeds its maps with data from a number of open data sources, including the crowdsourced OpenStreetMap.

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OpenStreetMap is essentially Wikipedia in map form. With millions of users, OSM allows anyone to alter its map data, much like you can do on a Wiki. OSM users can add missing roads or new neighborhoods. They can even change the name of existing cities.

While its possible one of Mapbox’s other various data sources could have also been changed, the OpenStreetMap user page of the account responsible for the vandalism has archived the very changes that later showed up on the applications and websites using Mapbox.

Twenty days ago, user MedwedianPresident made a number of edits to OSM disguised as minor alterations to Auckland City Park and the City of London. Looking into the actual edits, however, shows what MedwedianPresident actually did. Stretches of New York were renamed the Ku Klux Klan Highway, Pedophile Bridge, Zionist Cannibal Drive, and the Adolf Hitler Memorial Tunnel. Sections of London were changed to Adolf Hitler Boulevard, Donald Trump Avenue, and Fuck Road.

The changes were caught pretty quickly on OpenStreetMap, with another user “reverting vandalism” and changing the names back. According to MedwedianPresident’s OSM page, an active block was placed on the account 19 days ago, a day following the vandalism. It’s unclear how the OSM info that was changed back weeks ago rolled out through Mapbox’s mapping data today.

Mashable reached out to the Anti-Defamation League after noticing that the ADL’s H.E.A.T. map, which tracks incidents of hate and anti-Semitism, was powered by Mapbox. A spokesperson told us that they do not believe its H.E.A.T. map was affected by this and forwarded us a Twitter statement on the issue as well as a tweet from its NY/NJ regional director.

.@Mapbox, it’s being reported that New York is labeled as “jewtropolis” on your maps, which are used by @Snap, @FoursquareAPI, @FinancialTimes, @evernote and others. Have you taken down this anti-Semitic vandalism yet? We’re ready to help. https://t.co/NBdhItt7IY — ADL (@ADL_National) August 30, 2018

.@ADL_NYNJ is deeply concerned at reports of mapping sites referring to #NewYork as #Jewtropolis. This is #Antisemitic and we are calling on companies to fix this immediately #noplaceforhate https://t.co/tSEqskUUEh — Evan R. Bernstein (@bernstein_evan) August 30, 2018

In an official statement provided to Mashable by Mapbox, it seems that the changes were in fact flagged by its AI technology, which “prevents malicious edits from entering the system from any third party data source.” However, human error caused the anti-Semitic edits to be pushed out live. Mapbox says they removed the edits within an hour.

The act of hate speech that has affected our map users has been resolved. We will not accept hatred on our platform. We removed the attack within an hour of discovery and this is cleared on all maps at this time. Full statement here: https://t.co/V8KWZTSeT9 pic.twitter.com/3tyOmyWAlv — Mapbox (@Mapbox) August 30, 2018

Mapbox did not confirm OpenStreetMap user MedwedianPresident was the culprit. Instead, it said it currently does not know where the edits came from — it currently uses “over 130 sets of data” — but says that it currently has security experts “working to determine the exact origin of this malicious hate speech.”