New Kindle e-reader jailbreak works on 2013 and later models

A jailbreak method has been released for Amazon’s Kindle e-readers. It works on ten different Kindle models, as long as the firmware running on it is not newer than version 5.13.3, which came out in October of 2020.

The exploit works from firmware version 5.10.3. However, interested users can manually upgrade to any version of the firmware they want, but downgrading is not possible on a Kindle. The jailbreak maker further warns that on versions numbered 5.12.x and newer, there is no foolproof way to prevent automatic updates, so they should proceed with caution to avoid upgrading to a non-compatible version. The supported models that author tyrol mentions are the Kindle Oasis 1, 2 and 3, Paperwhite 2, 3 and 4, Basic 1, 2 and 3, and the Kindle Voyage.

The jailbreak takes advantage of the KindleDrip vulnerability. That is a chain of vulnerabilities, but it specifically concerns a vulnerability in the built-in browser of the e-readers. There is a possibility to create a buffer overflow via a modified .jxr image file, after which the stackdumpd process, which has root access and its own vulnerability, is hijacked. What the jailbreak does after that, the author does not describe. They only say that the browser crashes, the Kindle reboots and the jailbreak is complete after that.

The jailbreak makes it possible to customize the interface, set new fonts and screensavers, remove ads and, perhaps most interestingly, install another app for reading e-books. Unlike most other e-readers, Kindles do not support the open ePub file format. Kindle firmware uses the Linux kernel.