Unchecked NULL pointer usage in xkbcommon before 0.8.1 could be used by local attackers to crash (NULL pointer dereference) the xkbcommon parser by supplying a crafted keymap file, because the XkbFile for an xkb_geometry section was mishandled. Upstream patch: https://github.com/xkbcommon/libxkbcommon/commit/917636b1d0d70205a13f89062b95e3a0fc31d4ff References: https://lists.freedesktop.org/archives/wayland-devel/2018-August/039232.html
The parser implemented in parser.y returns NULL when a xkb_geometry FileType is parsed, but some parts of the code, like parser.y:parse(), do not handle NULL values, causing the application to crash.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2019:2079 https://access.redhat.com/errata/RHSA-2019:2079
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2018-15855