UBUNTU-CVE-2020-11739

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Source
https://ubuntu.com/security/notices/UBUNTU-CVE-2020-11739
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-11739.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2020-11739
Related
Published
2020-04-14T13:15:00Z
Modified
2020-04-14T13:15:00Z
Severity
  • 7.8 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H CVSS Calculator
Summary
[none]
Details

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service or possibly gain privileges because of missing memory barriers in read-write unlock paths. The read-write unlock paths don't contain a memory barrier. On Arm, this means a processor is allowed to re-order the memory access with the preceding ones. In other words, the unlock may be seen by another processor before all the memory accesses within the "critical" section. As a consequence, it may be possible to have a writer executing a critical section at the same time as readers or another writer. In other words, many of the assumptions (e.g., a variable cannot be modified after a check) in the critical sections are not safe anymore. The read-write locks are used in hypercalls (such as grant-table ones), so a malicious guest could exploit the race. For instance, there is a small window where Xen can leak memory if XENMAPSPACEgranttable is used concurrently. A malicious guest may be able to leak memory, or cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded.

References

Affected packages

Ubuntu:Pro:16.04:LTS / xen

Package

Name
xen

Affected ranges

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

Affected versions

4.*

4.5.1-0ubuntu1
4.5.1-0ubuntu2
4.6.0-1ubuntu1
4.6.0-1ubuntu2
4.6.0-1ubuntu4
4.6.0-1ubuntu4.1
4.6.0-1ubuntu4.2
4.6.0-1ubuntu4.3
4.6.5-0ubuntu1
4.6.5-0ubuntu1.1
4.6.5-0ubuntu1.2
4.6.5-0ubuntu1.4

Ecosystem specific 

{
    "ubuntu_priority": "medium"
}

Ubuntu:Pro:18.04:LTS / xen

Package

Name
xen

Affected ranges

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

Affected versions

4.*

4.9.0-0ubuntu3
4.9.0-0ubuntu4
4.9.2-0ubuntu1

Ecosystem specific 

{
    "ubuntu_priority": "medium"
}

Ubuntu:20.04:LTS / xen

Package

Name
xen
Purl
pkg:deb/ubuntu/xen@4.11.3+24-g14b62ab3e5-1ubuntu2.3?arch=src?distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
4.11.3+24-g14b62ab3e5-1ubuntu2.3

Affected versions

4.*

4.9.2-0ubuntu2
4.9.2-0ubuntu6
4.9.2-0ubuntu7
4.11.3+24-g14b62ab3e5-1ubuntu1
4.11.3+24-g14b62ab3e5-1ubuntu2
4.11.3+24-g14b62ab3e5-1ubuntu2.2

Ecosystem specific 

{
    "availability": "No subscription required",
    "ubuntu_priority": "medium",
    "binaries": [
        {
            "xen-doc": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxengnttab1": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxendevicemodel1-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-hypervisor-4.11-armhf": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-hypervisor-4.9-armhf": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxenevtchn1-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxentoolcore1-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxentoollog1-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-hypervisor-common": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-hypervisor-4.9-arm64": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxenforeignmemory1": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxencall1": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-utils-common-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-utils-4.11-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxenmisc4.11-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-system-arm64": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xenstore-utils-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxenstore3.0": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-hypervisor-4.11-arm64": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxengnttab1-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxenstore3.0-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-hypervisor-4.9-amd64": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxenforeignmemory1-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxendevicemodel1": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxen-dev": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-system-amd64": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxentoolcore1": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxencall1-dbgsym": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xenstore-utils": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxenevtchn1": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-utils-common": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-system-armhf": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxentoollog1": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-hypervisor-4.11-amd64": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "xen-utils-4.11": "4.11.3+24-g14b62ab3e5-1ubuntu2.3",
            "libxenmisc4.11": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        }
    ]
}