LibYAML is a YAML 1.1 parser and emitter written in C.
The yaml_parser_scan_uri_escapes() function does not properly expand strings passed as input, which can result in a heap-based buffer overflow.
An attacker could provide a specially-crafted YAML document, which, when parsed by LibYAML, could result in arbitrary code execution or cause the application to crash.
There is no known workaround at this time.
All LibYAML users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-libs/libyaml-0.1.6"
Packages which depend on this library may need to be recompiled. Tools such as revdep-rebuild may assist in identifying these packages.