GNOME Shell provides core user interface functions for the GNOME desktop, like switching to windows and launching applications. gettext contains the GNU locale utilities. libcroco is a standalone CSS2 parsing and manipulation library.
The cr_parser_parse_any_core function in libcroco's cr-parser.c does not limit recursion, leading to a denial of service via a stack overflow when trying to parse crafted CSS. Gnome Shell and gettext bundle libcroco in their own sources and thus are potentially vulnerable as well.
An attacker with control over the input to the library can cause a denial of service.
There is no known workaround at this time.
All gettext users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-devel/gettext-0.21"
All Gnome Shell users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=gnome-base/gnome-shell-3.36.7"
All libcroco users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-libs/libcroco-0.6.13"