CVE-2021-3782: Wayland

Medium severity, CVSS 6.6. EPSS: 0.3% chance of exploitation in the next 30 days.

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 products

• Wayland Wayland: before 1.20.91 (fixed in 1.20.91)

Published 2022-09-23. Last modified 2026-06-17.