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.

🗓️ 27 Sep 2022 07:00:00Reported by MicrosoftType 

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