Valgrind is an open-source memory debugger.
Tavis Ormandy reported that Valgrind loads a .valgrindrc file in the current working directory, executing commands specified there.
A local attacker could prepare a specially crafted .valgrindrc file and entice a user to run Valgrind from the directory containing that file, resulting in the execution of arbitrary code with the privileges of the user running Valgrind.
Do not run "valgrind" from untrusted working directories.
All Valgrind users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-util/valgrind-3.4.0"