pyenv 1.2.24 through 2.3.2 allows local users to gain privileges via a .python-version file in the current working directory. An attacker can craft a Python version string in .python-version to execute shims under their control. (Shims are executables that pass a command along to a specific version of pyenv. The version string is used to construct the path to the command, and there is no validation of whether the version specified is a valid version. Thus, relative path traversal can occur.)
https://github.com/pyenv/pyenv/commit/22fa683571d98b59ea16e5fe48ac411c67939653