UBUNTU-CVE-2021-20181

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Source
https://ubuntu.com/security/CVE-2021-20181
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-20181.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2021-20181
Upstream
Downstream
Related
Published
2021-02-01T00:00:00Z
Modified
2025-09-08T16:46:54Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.

References

Affected packages

Ubuntu:Pro:14.04:LTS / qemu

Package

Name
qemu
Purl
pkg:deb/ubuntu/qemu@2.0.0+dfsg-2ubuntu1.47+esm4?arch=source&distro=esm-infra-legacy/trusty

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.5.0+dfsg-3ubuntu5
1.5.0+dfsg-3ubuntu6
1.6.0+dfsg-2ubuntu1
1.6.0+dfsg-2ubuntu2
1.6.0+dfsg-2ubuntu3
1.6.0+dfsg-2ubuntu4
1.7.0+dfsg-2ubuntu1
1.7.0+dfsg-2ubuntu2
1.7.0+dfsg-2ubuntu3
1.7.0+dfsg-2ubuntu4
1.7.0+dfsg-2ubuntu5
1.7.0+dfsg-2ubuntu7
1.7.0+dfsg-2ubuntu8
1.7.0+dfsg-2ubuntu9
1.7.0+dfsg-3ubuntu1~ppa1
1.7.0+dfsg-3ubuntu1
1.7.0+dfsg-3ubuntu2
1.7.0+dfsg-3ubuntu3
1.7.0+dfsg-3ubuntu4
1.7.0+dfsg-3ubuntu5
1.7.0+dfsg-3ubuntu6
1.7.0+dfsg-3ubuntu7

2.*

2.0.0~rc1+dfsg-0ubuntu1
2.0.0~rc1+dfsg-0ubuntu2
2.0.0~rc1+dfsg-0ubuntu3
2.0.0~rc1+dfsg-0ubuntu3.1
2.0.0+dfsg-2ubuntu1
2.0.0+dfsg-2ubuntu1.1
2.0.0+dfsg-2ubuntu1.2
2.0.0+dfsg-2ubuntu1.3
2.0.0+dfsg-2ubuntu1.5
2.0.0+dfsg-2ubuntu1.6
2.0.0+dfsg-2ubuntu1.7
2.0.0+dfsg-2ubuntu1.8
2.0.0+dfsg-2ubuntu1.9
2.0.0+dfsg-2ubuntu1.10
2.0.0+dfsg-2ubuntu1.11
2.0.0+dfsg-2ubuntu1.13
2.0.0+dfsg-2ubuntu1.14
2.0.0+dfsg-2ubuntu1.15
2.0.0+dfsg-2ubuntu1.16
2.0.0+dfsg-2ubuntu1.17
2.0.0+dfsg-2ubuntu1.18
2.0.0+dfsg-2ubuntu1.19
2.0.0+dfsg-2ubuntu1.20
2.0.0+dfsg-2ubuntu1.21
2.0.0+dfsg-2ubuntu1.22
2.0.0+dfsg-2ubuntu1.24
2.0.0+dfsg-2ubuntu1.25
2.0.0+dfsg-2ubuntu1.26
2.0.0+dfsg-2ubuntu1.27
2.0.0+dfsg-2ubuntu1.28
2.0.0+dfsg-2ubuntu1.29
2.0.0+dfsg-2ubuntu1.30
2.0.0+dfsg-2ubuntu1.31
2.0.0+dfsg-2ubuntu1.32
2.0.0+dfsg-2ubuntu1.33
2.0.0+dfsg-2ubuntu1.34
2.0.0+dfsg-2ubuntu1.35
2.0.0+dfsg-2ubuntu1.36
2.0.0+dfsg-2ubuntu1.38
2.0.0+dfsg-2ubuntu1.39
2.0.0+dfsg-2ubuntu1.40
2.0.0+dfsg-2ubuntu1.41
2.0.0+dfsg-2ubuntu1.42
2.0.0+dfsg-2ubuntu1.43
2.0.0+dfsg-2ubuntu1.44
2.0.0+dfsg-2ubuntu1.45
2.0.0+dfsg-2ubuntu1.46
2.0.0+dfsg-2ubuntu1.47
2.0.0+dfsg-2ubuntu1.47+esm1
2.0.0+dfsg-2ubuntu1.47+esm2
2.0.0+dfsg-2ubuntu1.47+esm3
2.0.0+dfsg-2ubuntu1.47+esm4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "qemu",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-common",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-guest-agent",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-keymaps",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-kvm",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system-aarch64",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system-arm",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system-common",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system-mips",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system-misc",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system-ppc",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system-sparc",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-system-x86",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-user",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-user-static",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        },
        {
            "binary_name": "qemu-utils",
            "binary_version": "2.0.0+dfsg-2ubuntu1.47+esm4"
        }
    ]
}

Ubuntu:16.04:LTS / qemu

Package

Name
qemu
Purl
pkg:deb/ubuntu/qemu@1:2.5+dfsg-5ubuntu10.49?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:2.5+dfsg-5ubuntu10.49

Affected versions

1:2.*

1:2.3+dfsg-5ubuntu9
1:2.3+dfsg-5ubuntu10
1:2.4+dfsg-4ubuntu1
1:2.4+dfsg-4ubuntu2
1:2.4+dfsg-4ubuntu3
1:2.4+dfsg-5ubuntu3
1:2.5+dfsg-1ubuntu2
1:2.5+dfsg-1ubuntu3
1:2.5+dfsg-1ubuntu4
1:2.5+dfsg-1ubuntu5
1:2.5+dfsg-5ubuntu1
1:2.5+dfsg-5ubuntu2
1:2.5+dfsg-5ubuntu4
1:2.5+dfsg-5ubuntu6
1:2.5+dfsg-5ubuntu7
1:2.5+dfsg-5ubuntu10
1:2.5+dfsg-5ubuntu10.1
1:2.5+dfsg-5ubuntu10.2
1:2.5+dfsg-5ubuntu10.3
1:2.5+dfsg-5ubuntu10.4
1:2.5+dfsg-5ubuntu10.5
1:2.5+dfsg-5ubuntu10.6
1:2.5+dfsg-5ubuntu10.7
1:2.5+dfsg-5ubuntu10.8
1:2.5+dfsg-5ubuntu10.9
1:2.5+dfsg-5ubuntu10.10
1:2.5+dfsg-5ubuntu10.11
1:2.5+dfsg-5ubuntu10.13
1:2.5+dfsg-5ubuntu10.14
1:2.5+dfsg-5ubuntu10.15
1:2.5+dfsg-5ubuntu10.16
1:2.5+dfsg-5ubuntu10.20
1:2.5+dfsg-5ubuntu10.21
1:2.5+dfsg-5ubuntu10.22
1:2.5+dfsg-5ubuntu10.24
1:2.5+dfsg-5ubuntu10.25
1:2.5+dfsg-5ubuntu10.26
1:2.5+dfsg-5ubuntu10.28
1:2.5+dfsg-5ubuntu10.29
1:2.5+dfsg-5ubuntu10.30
1:2.5+dfsg-5ubuntu10.31
1:2.5+dfsg-5ubuntu10.32
1:2.5+dfsg-5ubuntu10.33
1:2.5+dfsg-5ubuntu10.34
1:2.5+dfsg-5ubuntu10.35
1:2.5+dfsg-5ubuntu10.36
1:2.5+dfsg-5ubuntu10.37
1:2.5+dfsg-5ubuntu10.38
1:2.5+dfsg-5ubuntu10.39
1:2.5+dfsg-5ubuntu10.40
1:2.5+dfsg-5ubuntu10.41
1:2.5+dfsg-5ubuntu10.42
1:2.5+dfsg-5ubuntu10.43
1:2.5+dfsg-5ubuntu10.44
1:2.5+dfsg-5ubuntu10.45
1:2.5+dfsg-5ubuntu10.46
1:2.5+dfsg-5ubuntu10.47
1:2.5+dfsg-5ubuntu10.48

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "qemu",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-block-extra",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-guest-agent",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-kvm",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-aarch64",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-arm",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-common",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-mips",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-misc",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-ppc",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-s390x",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-sparc",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-system-x86",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-user",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-user-binfmt",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-user-static",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        },
        {
            "binary_name": "qemu-utils",
            "binary_version": "1:2.5+dfsg-5ubuntu10.49"
        }
    ]
}

Ubuntu:18.04:LTS / qemu

Package

Name
qemu
Purl
pkg:deb/ubuntu/qemu@1:2.11+dfsg-1ubuntu7.35?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:2.11+dfsg-1ubuntu7.35

Affected versions

1:2.*

1:2.10+dfsg-0ubuntu3
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

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "qemu",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-block-extra",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-guest-agent",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-kvm",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system-arm",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system-common",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system-mips",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system-misc",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system-ppc",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system-s390x",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system-sparc",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-system-x86",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-user",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-user-binfmt",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-user-static",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        },
        {
            "binary_name": "qemu-utils",
            "binary_version": "1:2.11+dfsg-1ubuntu7.35"
        }
    ]
}

Ubuntu:20.04:LTS / qemu

Package

Name
qemu
Purl
pkg:deb/ubuntu/qemu@1:4.2-3ubuntu6.12?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:4.2-3ubuntu6.12

Affected versions

1:4.*

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

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "qemu",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-block-extra",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-guest-agent",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-kvm",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-arm",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-common",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-data",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-gui",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-mips",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-misc",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-ppc",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-s390x",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-sparc",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-x86",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-x86-microvm",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-system-x86-xen",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-user",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-user-binfmt",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-user-static",
            "binary_version": "1:4.2-3ubuntu6.12"
        },
        {
            "binary_name": "qemu-utils",
            "binary_version": "1:4.2-3ubuntu6.12"
        }
    ]
}