Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of service. The attacker opens the HTTP/2 window so the peer can send without constraint; however, they leave the TCP window closed so the peer cannot actually write (many of) the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the servers queue the responses, this can consume excess memory, CPU, or both.
i915_gem_userptr_get_pages in drivers/gpu/drm/i915/i915_gem_userptr.c in the Linux kernel 4.15.0 on Ubuntu 18.04.2 allows local users to cause a denial of service (NULL pointer dereference and BUG) or possibly have unspecified other impact via crafted ioctl calls to /dev/dri/card0.
In the cron package through 3.0pl1-128 on Debian, and through 3.0pl1-128ubuntu2 on Ubuntu, the postinst maintainer script allows for group-crontab-to-root privilege escalation via symlink attacks against unsafe usage of the chown and chmod programs.