(CBS NEWS) -- United Airlines said in a "Safety Alert" emailed to employees that information regarding its flight deck access security procedures "may have been compromised," CBS News transportation correspondent Kris Van Cleave reports.
It also said in an emailed statement to CBS News that "some cockpit door access information may have been made public."
The email to employees, sent on Saturday, was short on specifics. But the airline said it was working on a "corrective action plan," noting that pilots have been asked to review procedures during briefings.
The emailed alert reminded employees that "the risk of a breach of the flight deck door is strongly mitigated by carefully following the flight deck security procedures," adding, "remember this information is sensitive security information and sharing this with anyone not authorized or who does not have a need to know is strictly prohibited."
Cockpit doors were fortified and secured following the 9/11 hijackings.