CVE-2021-3782
Published: September 23, 2022Last modified: November 8, 2023
Description
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 6.6 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | LOW |
| Integrity impact | LOW |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | wayland | Not affected (1.21.0-r1) |
| Stream | wayland | Not affected (1.20.0-r0) |