More than 1,000 Citibike members had their personal and financial information exposed due to a software glitch on the bikeshare program's website, officials said.
The names, addresses and credit card information of nearly 1,200 members was briefly accessible for one day in April on a back page of the bikeshare's website, according to a letter sent to the customers affected by the breach.
There is no evidence that any of the information was maliciously accessed or misused, the letter noted.
The error was corrected as soon as it was discovered, according to the letter.
More than 60,000 annual members have signed up for Citibike since its launch in late May.