Twitter informed users on Thursday that their personal information may have been exposed due to the way the Firefox web browser stores cached data.
The social media giant discovered recently that Firefox’s cache stored some private information associated with the use of Twitter, including sent or received direct messages and the downloaded data archive. However, this would only be problematic on shared computers.
“We recently learned that the way Mozilla Firefox stores cached data may have resulted in non-public information being inadvertently stored in the browser’s cache,” Twitter explained. “This means that if you accessed Twitter from a shared or public computer via Mozilla Firefox and took actions like downloading your Twitter data archive or sending or receiving media via Direct Message, this information may have been stored in the browser’s cache even after you logged out of Twitter.”
The company added in a message posted on Twitter, “There isn’t a standard for how browsers cache downloaded data. We noticed that the way Firefox stores cached Twitter data is different (but not wrong) than other browsers and could put your non-public info at risk.”
Firefox only stores cached data for 7 days, which means the Twitter data would have only been exposed for a limited period of time. Users can also manually clear the cache, which Twitter recommends for users who accessed Twitter from a shared or public device.
Twitter has made some changes on its end to ensure Firefox no longer stores potentially sensitive information belonging to its users. Safari and Chrome do not appear to be impacted.
Twitter has disclosed several security and privacy issues over the past few years, including related to the use of account security information for advertising, the Android app exposing protected tweets, an API vulnerability exploited to match usernames to phone numbers, the Android app allowing hackers to obtain sensitive data and hijack accounts, and direct messages being exposed to third-party developers.
Related: Twitter Moves to Curb Manipulated Content Including ‘Deepfakes’
Related: Twitter Promises Increased Transparency With New Privacy Center
Related: Twitter, Facebook User Data Improperly Accessed via Malicious SDKs
Related: Twitter Users Can Now Use 2FA Without a Phone Number

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.
More from Eduard Kovacs
- UK Car Retailer Arnold Clark Hit by Ransomware
- EV Charging Management System Vulnerabilities Allow Disruption, Energy Theft
- Unpatched Econolite Traffic Controller Vulnerabilities Allow Remote Hacking
- Google Fi Data Breach Reportedly Led to SIM Swapping
- Microsoft’s Verified Publisher Status Abused in Email Theft Campaign
- British Retailer JD Sports Discloses Data Breach Affecting 10 Million Customers
- Meta Awards $27,000 Bounty for 2FA Bypass Vulnerability
- Industry Reactions to Hive Ransomware Takedown: Feedback Friday
Latest News
- Google Shells Out $600,000 for OSS-Fuzz Project Integrations
- F5 BIG-IP Vulnerability Can Lead to DoS, Code Execution
- Flaw in Cisco Industrial Appliances Allows Malicious Code to Persist Across Reboots
- UK Car Retailer Arnold Clark Hit by Ransomware
- Dealing With the Carcinization of Security
- HeadCrab Botnet Ensnares 1,200 Redis Servers for Cryptomining
- Cyber Insights 2023 | Supply Chain Security
- Cyber Insights 2023 | Regulations
