linux — security advisory
In the Linux kernel, the following vulnerability has been resolved: drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap drm_gem_ttm_mmap() drops a reference to the gem object on success. If the gem object's refcount == 1 on entry to drm_gem_prime_mmap(), that drop will free the gem object, and the subsequent drm_gem_object_get() will be a UAF. Fix by grabbing a reference before calling the mmap helper. This issue was forseen when the reference dropping was adding in commit 9786b65bc61ac ("drm/ttm: fix mmap refcounting"): "For that to work properly the drm_gem_object_get() call in drm_gem_ttm_mmap() must be moved so it happens before calling obj->funcs->mmap(), otherwise the gem refcount would go down to zero."
- Products
- linux
- Affected versions
- Not specified
- Fixed versions
- 5.15.5-1
- CVEs
- CVE-2021-47200
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 01:12 UTC · Revision 1
Source evidence
In the Linux kernel, the following vulnerability has been resolved: drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap drm_gem_ttm_mmap() drops a reference to the gem object on success. If the gem object's refcount == 1 on entry to drm_gem_prime_mmap(), that drop will free the gem object, and the subsequent drm_gem_object_get() will be a UAF. Fix by grabbing a reference before calling the mmap helper. This issue was forseen when the reference dropping was adding in commit 9786b65bc61ac ("drm/ttm: fix mmap refcounting"): "For that to work properly the drm_gem_object_get() call in drm_gem_ttm_mmap() must be moved so it happens before calling obj->funcs->mmap(), otherwise the gem refcount would go down to zero."
osv:DEBIAN-CVE-2021-47200
linux
Fixed versions: 5.15.5-1
linux
Fixed versions: 5.15.5-1
linux
Fixed versions: 5.15.5-1
Complete source record
{
"id": "5ce7112541441c0a80092a27cf1bd44c0495b869becaca1ee89c4bb3fefe264e",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-47200",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2021-47200",
"summary": "In the Linux kernel, the following vulnerability has been resolved: drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap drm_gem_ttm_mmap() drops a reference to the gem object on success. If the gem object's refcount == 1 on entry to drm_gem_prime_mmap(), that drop will free the gem object, and the subsequent drm_gem_object_get() will be a UAF. Fix by grabbing a reference before calling the mmap helper. This issue was forseen when the reference dropping was adding in commit 9786b65bc61ac (\"drm/ttm: fix mmap refcounting\"): \"For that to work properly the drm_gem_object_get() call in drm_gem_ttm_mmap() must be moved so it happens before calling obj->funcs->mmap(), otherwise the gem refcount would go down to zero.\"",
"evidence": "osv:DEBIAN-CVE-2021-47200",
"products": [
{
"name": {
"value": "linux",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.15.5-1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
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"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
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"value": "5.15.5-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
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},
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"fixed_versions": [
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"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2021-47200",
"aliases": [
"DEBIAN-CVE-2021-47200"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.15.5-1"
}
]
}
],
"package": {
"name": "linux",
"purl": "pkg:deb/debian/linux?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47200.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.15.5-1"
}
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}
],
"package": {
"name": "linux",
"purl": "pkg:deb/debian/linux?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47200.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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{
"fixed": "5.15.5-1"
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],
"package": {
"name": "linux",
"purl": "pkg:deb/debian/linux?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47200.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:04:18.861075936Z",
"provider": "osv",
"upstream": [
"CVE-2021-47200"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2021-47200"
]
},
"related_cves": [
{
"value": "CVE-2021-47200",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 423336,
"published_at": "2024-04-10T19:15:48.077+00:00"
}