UBUNTU-CVE-2026-79603

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Source
https://ubuntu.com/security/CVE-2026-79603
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79603.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-79603
Upstream
  • CVE-2026-79603
Published
2026-09-08T12:00:00Z
Modified
2026-09-10T11:01:32Z
Severity
  • 4.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

x86 PV guests can free memory pages while still keeping a stale TLB entry pointing to them. A TLB flush is only issued by Xen (if needed) when the page is re-used. Since it's possible for the page to be scrubbed ahead of the TLB flush, there's a window where a PV guest can modify an already scrubbed page. Deployments using xsm=silo scrub-domheap with the aim of not allowing the exchange of information amongst guests are not effective in the presence of PV guests. All Xen versions from 4.13 onwards are vulnerable. Xen versions 4.12 and earlier are not vulnerable as they lack the scrub-domheap command line option. Only x86 PV guests can exploit the vulnerability.

References

Affected packages

Ubuntu:16.04:LTS
xen

Package

Name
xen
Purl
pkg:deb/ubuntu/xen?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown 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 

{
    "binaries": [
        {
            "binary_name": "libxen-4.6",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "libxenstore3.0",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.4-amd64",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.4-arm64",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.4-armhf",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.5-amd64",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.5-arm64",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.5-armhf",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.6-amd64",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.6-arm64",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-hypervisor-4.6-armhf",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-system-amd64",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-system-arm64",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-system-armhf",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-utils-4.6",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xen-utils-common",
            "binary_version": "4.6.5-0ubuntu1.4"
        },
        {
            "binary_name": "xenstore-utils",
            "binary_version": "4.6.5-0ubuntu1.4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79603.json"
Ubuntu:18.04:LTS
xen

Package

Name
xen
Purl
pkg:deb/ubuntu/xen?arch=source&distro=bionic

Affected ranges

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

Affected versions

4.*
4.9.0-0ubuntu3
4.9.0-0ubuntu4
4.9.2-0ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libxen-4.9",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "libxenstore3.0",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.6-amd64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.6-arm64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.6-armhf",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.7-amd64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.7-arm64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.7-armhf",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.8-amd64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.8-arm64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.8-armhf",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.9-amd64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.9-arm64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-hypervisor-4.9-armhf",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-system-amd64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-system-arm64",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-system-armhf",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-utils-4.9",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xen-utils-common",
            "binary_version": "4.9.2-0ubuntu1"
        },
        {
            "binary_name": "xenstore-utils",
            "binary_version": "4.9.2-0ubuntu1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79603.json"
Ubuntu:20.04:LTS
xen

Package

Name
xen
Purl
pkg:deb/ubuntu/xen?arch=source&distro=focal

Affected ranges

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

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
4.11.3+24-g14b62ab3e5-1ubuntu2.3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libxencall1",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "libxendevicemodel1",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "libxenevtchn1",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "libxenforeignmemory1",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "libxengnttab1",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "libxenmisc4.11",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "libxenstore3.0",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "libxentoolcore1",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "libxentoollog1",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-hypervisor-4.11-amd64",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-hypervisor-4.11-arm64",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-hypervisor-4.11-armhf",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-hypervisor-4.9-amd64",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-hypervisor-4.9-arm64",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-hypervisor-4.9-armhf",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-hypervisor-common",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-system-amd64",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-system-arm64",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-system-armhf",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-utils-4.11",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xen-utils-common",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        },
        {
            "binary_name": "xenstore-utils",
            "binary_version": "4.11.3+24-g14b62ab3e5-1ubuntu2.3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79603.json"
Ubuntu:22.04:LTS
xen

Package

Name
xen
Purl
pkg:deb/ubuntu/xen?arch=source&distro=jammy

Affected ranges

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

Affected versions

4.*
4.11.4+24-gddaaccbbab-1ubuntu2
4.16.0-1~ubuntu2
4.16.0-1~ubuntu2.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libxencall1",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxendevicemodel1",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxenevtchn1",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxenforeignmemory1",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxengnttab1",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxenhypfs1",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxenmisc4.16",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxenstore4",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxentoolcore1",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "libxentoollog1",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-hypervisor-4.16-amd64",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-hypervisor-4.16-arm64",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-hypervisor-4.16-armhf",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-hypervisor-common",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-system-amd64",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-system-arm64",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-system-armhf",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-utils-4.16",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xen-utils-common",
            "binary_version": "4.16.0-1~ubuntu2.1"
        },
        {
            "binary_name": "xenstore-utils",
            "binary_version": "4.16.0-1~ubuntu2.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79603.json"
Ubuntu:24.04:LTS
xen

Package

Name
xen
Purl
pkg:deb/ubuntu/xen?arch=source&distro=noble

Affected ranges

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

Affected versions

4.*
4.17.2-1
4.17.2+55-g0b56bed864-1
4.17.2+76-ge1f9cb16e2-1
4.17.2+76-ge1f9cb16e2-1ubuntu1
4.17.3+10-g091466ba55-1
4.17.3+10-g091466ba55-1.1ubuntu2
4.17.3+10-g091466ba55-1.1ubuntu3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libxencall1t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxendevicemodel1t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxenevtchn1t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxenforeignmemory1t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxengnttab1t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxenhypfs1t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxenmisc4.17t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxenstore4t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxentoolcore1t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "libxentoollog1t64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-hypervisor-4.17-amd64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-hypervisor-4.17-arm64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-hypervisor-4.17-armhf",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-hypervisor-common",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-system-amd64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-system-arm64",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-system-armhf",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-utils-4.17",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xen-utils-common",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        },
        {
            "binary_name": "xenstore-utils",
            "binary_version": "4.17.3+10-g091466ba55-1.1ubuntu3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79603.json"
Ubuntu:26.04:LTS
xen

Package

Name
xen
Purl
pkg:deb/ubuntu/xen?arch=source&distro=resolute

Affected ranges

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

Affected versions

4.*
4.20.0+68-g35cb38b222-1
4.20.2+7-g1badcf5035-2
4.20.2+7-g1badcf5035-2build2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libxencall1",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxendevicemodel1",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxenevtchn1",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxenforeignmemory1",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxengnttab1",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxenhypfs1",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxenmisc4.20",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxenstore4",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxentoolcore1",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "libxentoollog1",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "xen-hypervisor-4.20-amd64",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "xen-hypervisor-4.20-arm64",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "xen-hypervisor-common",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "xen-system-amd64",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "xen-system-arm64",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "xen-utils-4.20",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "xen-utils-common",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        },
        {
            "binary_name": "xenstore-utils",
            "binary_version": "4.20.2+7-g1badcf5035-2build2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-79603.json"