A **Quizlet** user created a public flashcard set in February that appeared to expose highly confidential information about security procedures in US **Customs and Border Protection** facilities around Kingsville, Texas. The set, titled “USBP Review,” was publicly available until March 20, when it was made private shortly after *WIRED* contacted a phone number potentially linked to the user. Though an individual with the user’s name was listed at an address near a Kingsville CBP facility, verification of the flashcard set's creator as an active CBP agent or contractor remains unconfirmed. **CBP** Response "This incident is being reviewed by CBP’s Office of Professional Responsibility,” a CBP spokesperson stated to *WIRED*. "We will not be getting ahead of this review. A review should not be taken as an indication of wrongdoing." The **Department of Homeland Security** and **Immigration and Customs Enforcement** did not respond to requests for comment. Security Breach Details The public **Quizlet** set contained alleged codes for specific facility entrances. One card asked, “Checkpoint doors code?” with a four-digit combination listed as the answer. Similar cards revealed codes for other gates at the facility. The set also detailed immigration offenses, related federal charges, and internal procedures, including references to an “agents Resources Page.” Quizlet's Stance "We take reports of sensitive or inappropriate content seriously and act promptly when content is found to violate our policies,” a **Quizlet** spokesperson said. "We encourage anyone who encounters concerning material to report it directly from the flashcard set, class, or profile page, or to contact us so we can review and take appropriate action." Additional Information Exposed The cards also contained information about the Kingsville workforce’s area of responsibility, including county lines, the agency’s internal grid and zone system, and the names of 11 CBP “towers” in the area. One card detailed an internal system called “E3 BEST,” which allows officers to “record, investigate, and adjudicate secondary referrals at USBP checkpoints.” Recruitment Surge and Potential Risks This potential exposure of confidential information coincides with a rapid hiring surge at CBP, offering up to $60,000 in recruitment and retention incentives to new agents. ICE is also actively recruiting, offering significant signing bonuses and student loan repayment options. Other Potential Leaks Keyword searches revealed other **Quizlet** sets possibly created by new recruits to various DHS agencies, potentially offering insight into the training provided to these officers. Examples include sets related to ICE detention standards, transportation standards for ICE detainees, and a DHS insider threat training test with answers. One user created flashcard sets centered around US immigration law and immigration-related Spanish vocabulary, progressing from basic information to more complex concepts like CBP’s body-worn camera policies.