Dropbox, the popular online file storing system, said on Tuesday it has fixed a security flaw that could have allowed hackers to capture data stored in its service on Android devices via compromised third-party apps.

Dropbox, which has more than 300 million users, said it fixed the vulnerability a few months ago in the software it provides to third parties making apps that work with Dropbox. It warned all Android developers on Tuesday to update the latest version of the software.

"There are no reports or evidence to indicate the vulnerability was ever used to access user data," Dropbox said in a blog on its website.

Researchers at International Business Machines Corp initially discovered the flaw, and informed Dropbox, according to both companies.