On February 25, in a security notice Canonical published details about Transmission vulnerabilities for its Ubuntu 12.10, Ubuntu 12.04 LTS, and Ubuntu 11.10 operating systems.
According to Canonical, Transmission could be made to crash or run programs if it received specially crafted network traffic.
It was discovered that Transmission incorrectly handled certain micro transport protocol packets. A remote attacker could use this issue to cause a denial of service, or possibly execute arbitrary code.
For a more detailed description of the security problems, you can visit Canonical's security notification
Users can simply fix the security flaws by upgrading the operating systems, the transmission-common package, specific to each distribution.
A normal system update, executed with the Update Manager, will implement all the necessary changes. After a standard system update, you need to restart Transmission.