Security Experts:

Tumblr Vulnerability Exposed User Account Information

Tumblr on Wednesday disclosed a vulnerability that could have been exploited to obtain user account information, including email addresses and protected passwords.

According to the company, the flaw was related to the “Recommended Blogs” feature in the desktop version of Tumblr. The module shows logged-in users a list of blogs they may be interested in.

The security bug could have allowed an attacker to view account information associated with the blogs listed in the Recommended Blogs section by “using debugging software in a certain way.” Tumblr has not shared any other information on the vulnerability and how it could have been exploited.

The flaw exposed information such as name of the blog, email address, hashed and salted password of the Tumblr account, location, previously used email address, and last login IP.

“We’re not able to determine which specific accounts could have been affected by this bug, but our analysis has shown that the bug was rarely present,” Tumblr said.

The company claims a patch was implemented within 12 hours and there is no evidence that the vulnerability has been used for malicious purposes.

The vulnerability was reported by a researcher participating in the Oath bug bounty program, which also covers Tumblr. Oath, a Verizon subsidiary, is the umbrella company for Yahoo, AOL and other digital content services. Its bug bounty program has paid out over $1 million, with the highest offered rewards ranging between $10,000 and $15,000. It’s unclear how much the researcher earned for reporting the flaw disclosed by Tumblr this week.

“It’s our mission to provide a safe space for people to express themselves freely and form communities around things they love. We feel that this bug could have affected that experience. We want to be transparent with you about it. In our view, it’s simply the right thing to do,” the microblogging platform said.

This statement appears to be inspired by the backlash faced by Google recently for deciding not to immediately disclose a potentially critical API bug that exposed personal information from as many as 500,000 Google+ accounts. Google discovered the problem in March, but only notified users in October.

Back in 2016, Tumblr disclosed a breach affecting 65 million users who had registered accounts before early 2013.

Related: Data Aggregator LocalBlox Exposes 48 Million Records

Related: Facebook App Exposed Data of 120 Million Users

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.