Grindr, the world's largest gay dating app, has been providing private information about its users, including their users' HIV status, to a number of third-party companies, according to a report from BuzzFeed.

The report found Apptimize and Localytics, two firms that help optimize mobile applications, have received potentially sensitive information from Grindr that could be used to identify a specific user.

Norwegian nonprofit SINTEF first identified the issue after discovering that Grindr was sharing a wealth of user information with third-party companies. The information included user GPS position, “tribe” or gay subculture the user identifies with, sexuality, relationship status, ethnicity and unique phone ID. Included in the shared data are a user’s HIV status and their “last tested date.”

According to SINTEF, the information shared with Apptimize and Localytics was often shared in plaintext, meaning the content could easily be read if the data were to be intercepted by a hacker or malicious actor.

Given the wealth of user data and the sensitive nature of the information collected and shared, users could potentially be put at risk of being identified and outed were the data to fall into the wrong hands.

“The HIV status is linked to all the other information. That’s the main issue,” Antoine Pultier, a researcher at SINTEF, told BuzzFeed. “I think this is the incompetence of some developers that just send everything, including HIV status.”

Grindr has insisted that it does not sell any user information to third-party organizations. Instead, the company claims that it purchases services from Apptimize and Localytics in order to improve its product.

“Thousands of companies use these highly-regarded platforms. These are standard practices in the mobile app ecosystem,” Grindr Chief Technology Officer Scott Chen said in a statement. “No Grindr user information is sold to third parties. We pay these software vendors to utilize their services.”

Grindr, founded in 2009, often features advertisements for HIV testing sites. Grindr last week introduced a new, optional feature that will remind its users to get tested for HIV every three to six months. The feature points users to the nearest testing location and allows them to update their information to reflect their most recent test date.