CVE-2021-3782

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.

Weakness classification

• secalert@redhat.com: CWE-190
• nvd@nist.gov: CWE-190

Primary references

• secalert@redhat.com — Exploit, Issue Tracking, Patch, Third Party Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Exploit, Issue Tracking, Patch, Third Party Advisory