ubuntu-cve-2021-3748
Vulnerability from osv_ubuntu
Published
2021-08-31 00:00
Modified
2025-09-08 16:46
Summary
Details
A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non direct access region, due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU, resulting in a denial of service condition, or potentially execute code on the host with the privileges of the QEMU process.
Severity
7.5 (High)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "qemu",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-block-extra",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-guest-agent",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-kvm",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system-arm",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system-common",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system-mips",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system-misc",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system-ppc",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system-s390x",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system-sparc",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-system-x86",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-user",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-user-binfmt",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-user-static",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
},
{
"binary_name": "qemu-utils",
"binary_version": "1:2.11+dfsg-1ubuntu7.39"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "qemu",
"purl": "pkg:deb/ubuntu/qemu@1:2.11+dfsg-1ubuntu7.39?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.11+dfsg-1ubuntu7.39"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
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"1:2.10+dfsg-0ubuntu4",
"1:2.10+dfsg-0ubuntu5",
"1:2.11+dfsg-1ubuntu1",
"1:2.11+dfsg-1ubuntu2",
"1:2.11+dfsg-1ubuntu4",
"1:2.11+dfsg-1ubuntu5",
"1:2.11+dfsg-1ubuntu6",
"1:2.11+dfsg-1ubuntu7",
"1:2.11+dfsg-1ubuntu7.1",
"1:2.11+dfsg-1ubuntu7.2",
"1:2.11+dfsg-1ubuntu7.3",
"1:2.11+dfsg-1ubuntu7.4",
"1:2.11+dfsg-1ubuntu7.5",
"1:2.11+dfsg-1ubuntu7.6",
"1:2.11+dfsg-1ubuntu7.7",
"1:2.11+dfsg-1ubuntu7.8",
"1:2.11+dfsg-1ubuntu7.9",
"1:2.11+dfsg-1ubuntu7.10",
"1:2.11+dfsg-1ubuntu7.12",
"1:2.11+dfsg-1ubuntu7.13",
"1:2.11+dfsg-1ubuntu7.14",
"1:2.11+dfsg-1ubuntu7.15",
"1:2.11+dfsg-1ubuntu7.17",
"1:2.11+dfsg-1ubuntu7.18",
"1:2.11+dfsg-1ubuntu7.19",
"1:2.11+dfsg-1ubuntu7.20",
"1:2.11+dfsg-1ubuntu7.21",
"1:2.11+dfsg-1ubuntu7.22",
"1:2.11+dfsg-1ubuntu7.23",
"1:2.11+dfsg-1ubuntu7.25",
"1:2.11+dfsg-1ubuntu7.26",
"1:2.11+dfsg-1ubuntu7.27",
"1:2.11+dfsg-1ubuntu7.28",
"1:2.11+dfsg-1ubuntu7.29",
"1:2.11+dfsg-1ubuntu7.31",
"1:2.11+dfsg-1ubuntu7.32",
"1:2.11+dfsg-1ubuntu7.33",
"1:2.11+dfsg-1ubuntu7.34",
"1:2.11+dfsg-1ubuntu7.35",
"1:2.11+dfsg-1ubuntu7.36",
"1:2.11+dfsg-1ubuntu7.37",
"1:2.11+dfsg-1ubuntu7.38"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "qemu",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-block-extra",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-guest-agent",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-kvm",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-arm",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-common",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-data",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-gui",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-mips",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-misc",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-ppc",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-s390x",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-sparc",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-x86",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-x86-microvm",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-system-x86-xen",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-user",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-user-binfmt",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-user-static",
"binary_version": "1:4.2-3ubuntu6.21"
},
{
"binary_name": "qemu-utils",
"binary_version": "1:4.2-3ubuntu6.21"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "qemu",
"purl": "pkg:deb/ubuntu/qemu@1:4.2-3ubuntu6.21?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:4.2-3ubuntu6.21"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:4.0+dfsg-0ubuntu9",
"1:4.0+dfsg-0ubuntu10",
"1:4.2-1ubuntu1",
"1:4.2-1ubuntu2",
"1:4.2-3ubuntu1",
"1:4.2-3ubuntu2",
"1:4.2-3ubuntu3",
"1:4.2-3ubuntu4",
"1:4.2-3ubuntu5",
"1:4.2-3ubuntu6",
"1:4.2-3ubuntu6.1",
"1:4.2-3ubuntu6.2",
"1:4.2-3ubuntu6.3",
"1:4.2-3ubuntu6.4",
"1:4.2-3ubuntu6.5",
"1:4.2-3ubuntu6.6",
"1:4.2-3ubuntu6.7",
"1:4.2-3ubuntu6.8",
"1:4.2-3ubuntu6.9",
"1:4.2-3ubuntu6.10",
"1:4.2-3ubuntu6.11",
"1:4.2-3ubuntu6.12",
"1:4.2-3ubuntu6.14",
"1:4.2-3ubuntu6.15",
"1:4.2-3ubuntu6.16",
"1:4.2-3ubuntu6.17",
"1:4.2-3ubuntu6.18",
"1:4.2-3ubuntu6.19"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "qemu",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-block-extra",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-guest-agent",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-arm",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-common",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-data",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-gui",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-mips",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-misc",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-ppc",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-s390x",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-sparc",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-x86",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-x86-microvm",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-system-x86-xen",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-user",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-user-binfmt",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-user-static",
"binary_version": "1:6.2+dfsg-2ubuntu5"
},
{
"binary_name": "qemu-utils",
"binary_version": "1:6.2+dfsg-2ubuntu5"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "qemu",
"purl": "pkg:deb/ubuntu/qemu@1:6.2+dfsg-2ubuntu5?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1:6.2+dfsg-2ubuntu5"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1:6.0+dfsg-2expubuntu1",
"1:6.0+dfsg-2expubuntu2",
"1:6.0+dfsg-2expubuntu4"
]
}
],
"aliases": [],
"details": "A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor\u0027s address belongs to the non direct access region, due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU, resulting in a denial of service condition, or potentially execute code on the host with the privileges of the QEMU process.",
"id": "UBUNTU-CVE-2021-3748",
"modified": "2025-09-08T16:46:48Z",
"published": "2021-08-31T00:00:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2021-3748"
},
{
"type": "REPORT",
"url": "https://lists.nongnu.org/archive/html/qemu-devel/2021-09/msg00388.html"
},
{
"type": "ADVISORY",
"url": "https://ubuntu.com/security/notices/USN-5307-1"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2021-3748"
}
],
"related": [
"USN-5307-1"
],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2021-3748"
]
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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