libebml is a C++ library to parse EBML files.
On 32bit builds of libebml, the length of a string is miscalculated, potentially leading to an exploitable heap overflow.
An attacker able to provide arbitrary input to libebml could achieve arbitrary code execution.
There is no known workaround at this time.
Users of libebml on 32 bit architectures should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-libs/libebml-1.4.2"