Affected: wayland

An internal reference count is held on the buffer pool, incremented every time a new buffer is created from the pool. The reference count is maintained as an int; on LP64 systems this can cause the reference count to overflow if the client creates a large number of wl_shm buffer objects, or if it can coerce the server to create a large number of external references to the buffer storage. With the reference count overflowing, a use-after-free can be constructed on the wl_shm_pool tracking structure, where values may be incremented or decremented; it may also be possible to construct a limited oracle to leak 4 bytes of server-side memory to the attacking client at a time.

Affected: Ubuntu:18.04:LTS: wayland, Ubuntu:20.04:LTS: wayland, Ubuntu:22.04:LTS: wayland

It was discovered that Wayland incorrectly handled reference counting certain objects. An attacker could use this issue to cause Wayland to crash, resulting in a denial of service, or possibly execute arbitrary code.