I2P is an anonymity network, somewhat analogous to Tor, that encrypts all of its communications from end to end and enables private and anonymous use of the Internet and resources such as email, chat and Web browsing. Unlike Tor, however, I2P is a packet switched network, rather than a circuit switched one, and the communications its users send and receive are message-based. Each I2P node has an identical level of importance in the network and there are no central servers routing traffic.
Exodus researchers said that the flaw they discovered is present in TAILS for several versions, meaning its effect could be quite widespread.
“The vulnerability we will be disclosing is specific to I2P. I2P currently boasts about 30,000 active peers. Since I2P has been bundled with Tails since version 0.7, Tails is by far the most widely adopted I2P usage. The I2P vulnerability works on default, fully patched installation of Tails. No settings or configurations need to be changed for the exploit to work,” the Exodus team wrote in a post explaining a bit about the flaw."