{
  "cveId": "CVE-2020-11739",
  "url": "https://patchblox.com/security/cve/CVE-2020-11739",
  "summary": "CVE-2020-11739 is fixed in 22 products on 1 platform, first by libxencall1 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3, released September 23, 2020. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "libxencall1: An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service or possibly gain...",
  "description": "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\u0027t 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 \u0022critical\u0022 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 XENMAPSPACE_grant_table 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.",
  "published": "2020-04-14T06:15:00Z",
  "severity": "Medium",
  "epss": 0.00288,
  "epssPercentile": 0.21419,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libxencall1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxencall1 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxencall1-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxendevicemodel1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxendevicemodel1 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxendevicemodel1-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxenevtchn1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxenevtchn1 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxenevtchn1-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxenforeignmemory1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxenforeignmemory1 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxenforeignmemory1-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxengnttab1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxengnttab1 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxengnttab1-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxenmisc4.11",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxenmisc4.11 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxenmisc4.11-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxenstore3.0",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxenstore3.0 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxenstore3.0-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxentoolcore1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxentoolcore1 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxentoolcore1-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libxentoollog1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "libxentoollog1 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libxentoollog1-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-hypervisor-4.11-amd64",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-hypervisor-4.11-amd64 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-hypervisor-4.11-amd64-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-hypervisor-4.11-arm64",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-hypervisor-4.11-arm64 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-hypervisor-4.11-arm64-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-hypervisor-4.11-armhf",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-hypervisor-4.11-armhf 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-hypervisor-4.11-armhf-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-hypervisor-4.9-amd64",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-hypervisor-4.9-amd64 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-hypervisor-4.9-amd64-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-hypervisor-4.9-arm64",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-hypervisor-4.9-arm64 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-hypervisor-4.9-arm64-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-hypervisor-4.9-armhf",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-hypervisor-4.9-armhf 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-hypervisor-4.9-armhf-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-hypervisor-common",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-hypervisor-common 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-hypervisor-common-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-system-amd64",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-system-amd64 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-system-amd64-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-system-arm64",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-system-arm64 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-system-arm64-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-system-armhf",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-system-armhf 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-system-armhf-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-utils-4.11",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-utils-4.11 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-utils-4.11-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xen-utils-common",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xen-utils-common 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xen-utils-common-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    },
    {
      "platform": "linux",
      "product": "xenstore-utils",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "fix": "xenstore-utils 4.11.3\u002B24-g14b62ab3e5-1ubuntu2.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xenstore-utils-4.11.3-24-g14b62ab3e5-1ubuntu2.3",
      "released": "2020-09-23T15:15:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}