title: Improper i/o watch removal in tls handshake can lead to remote unauthenticated denial of service
description: A flaw was found in the QEMU built-in VNC server. When a client connects to the VNC server, QEMU checks whether the current number of connections crosses a certain threshold and if so, cleans up the previous connection. If the previous connection happens to be in the handshake phase and fails, QEMU cleans up the connection again, resulting in a NULL pointer dereference issue. This could allow a remote unauthenticated client to cause a denial of service.
problem types: NULL Pointer Dereference
affected:
{
product: qemu
vendor: n/a
defaultStatus: affected
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 6
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: qemu-kvm
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:6
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 7
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: qemu-kvm
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:7
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 7
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: qemu-kvm-ma
defaultStatus: affected
cpes: cpe:/o:redhat:enterprise_linux:7
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: virt:rhel/qemu-kvm
defaultStatus: affected
cpes: cpe:/o:redhat:enterprise_linux:8
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8 Advanced Virtualization
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: virt:av/qemu-kvm
defaultStatus: affected
cpes: cpe:/a:redhat:advanced_virtualization:8::el8
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: qemu-kvm
defaultStatus: affected
cpes: cpe:/o:redhat:enterprise_linux:9
}
{
vendor: Red Hat
product: Red Hat OpenStack Platform 13 (Queens)
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: qemu-kvm-rhev
defaultStatus: affected
cpes: cpe:/a:redhat:openstack:13
}
{
product: Fedora
vendor: Fedora
collectionURL: https://packages.fedoraproject.org/
packageName: qemu
defaultStatus: affected
}
{
product: Extra Packages for Enterprise Linux
vendor: Fedora
collectionURL: https://packages.fedoraproject.org/
packageName: qemu
defaultStatus: unaffected
}
metrics:
other: [
content: {'value': 'Important', 'namespace': 'https://access.redhat.com/security/updates/classification/'}
type: Red Hat severity rating
]