Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-3782
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 11:52 UTC · Revision 1
Source evidence
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.
osv:CVE-2021-3782
Complete source record
{
"id": "708823b089991a5073dbc5b597b6000bdc8b619338c938834541e658c7bcbf27",
"url": "https://osv.dev/vulnerability/CVE-2021-3782",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-3782",
"summary": "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.",
"evidence": "osv:CVE-2021-3782",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2021-3782",
"aliases": [
"CVE-2021-3782"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://gitlab.freedesktop.org/wayland/wayland",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "73d4d2410e2e0d0579bacc7f87d37bf4ec15cbbb"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:wayland:wayland:*:*:*:*:*:*:*:*",
"range": [
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},
{
"fixed": "1.20.91"
}
],
"source": "CPE_RANGE"
}
]
}
}
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3782.json"
}
}
],
"modified": "2026-10-20T10:54:52.248053222Z",
"provider": "osv",
"references": [
"https://gitlab.freedesktop.org/wayland/wayland/-/issues/224"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2021-3782",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 386311,
"published_at": "2022-09-23T16:15:10.143+00:00"
}