Apple is aware of and prepping a fix for an issue that results in email attachments not being properly encrypted in versions of the iOS mobile operating system.

“We're aware of the issue and are working on a fix which we will deliver in a future software update,” Apple said in a statement, according to a Monday post by news site

The issue was written about by security researcher Andreas Kurtz in a blog posted on April 23, in which Kurtz explains that the bug was validated after restoring an iPhone 4 to iOS 7.1.1, the latest version, and accessing the email folder in the file system. Kurtz said he later reproduced the flaw on an iPhone 5s and iPad 2 running iOS 7.0.4.

Until the issue is fixed, Kurtz suggested turning off mail synchronization on devices where the bootrom is exploitable.