A NULL pointer dereference flaw was discovered in libvirt before version 5.0.0 in the way it gets interface information through the QEMU agent. An attacker in a guest VM can use this flaw to crash libvirtd and cause a denial of service.
libvirt version before 4.2.0-rc1 is vulnerable to a resource exhaustion as a result of an incomplete fix for CVE-2018-5748 that affects QEMU monitor but now also triggered via QEMU guest agent.
libvirt before 2.0.0 improperly disables password checking when the password on a VNC server is set to an empty string, which allows remote attackers to bypass authentication and establish a VNC session by connecting to the server.
The qemu implementation in libvirt before 1.3.0 and Xen allows local guest OS users to cause a denial of service (host disk consumption) by writing to stdout or stderr.
libvirt before 1.2.12 allow remote authenticated users to obtain the VNC password by using the VIR_DOMAIN_XML_SECURE flag with a crafted (1) snapshot to the virDomainSnapshotGetXMLDesc interface or (2) image to the virDomainSaveImageGetXMLDesc interface.
The qemu implementation of virConnectGetAllDomainStats in libvirt before 1.2.11 does not properly handle locks when a domain is skipped due to ACL restrictions, which allows a remote authenticated users to cause a denial of service (deadlock or segmentation fault and crash) via a request to access the users does not have privileges to access.
The virDomainGetXMLDesc API in Libvirt before 1.2.11 allows remote read-only users to obtain the VNC password by using the VIR_DOMAIN_XML_MIGRATABLE flag, which triggers the use of the VIR_DOMAIN_XML_SECURE flag.
The libxlDomainGetNumaParameters function in the libxl driver (libxl/libxl_driver.c) in libvirt before 1.2.1 does not properly initialize the nodemap, which allows local users to cause a denial of service (invalid free operation and crash) or possibly execute arbitrary code via an inactive domain to the virsh numatune command.
Multiple race conditions in the (1) virDomainBlockStats, (2) virDomainGetBlockInf, (3) qemuDomainBlockJobImpl, and (4) virDomainGetBlockIoTune functions in libvirt before 1.2.1 do not properly verify that the disk is attached, which allows remote read-only attackers to cause a denial of service (libvirtd crash) via the virDomainDetachDeviceFlags command.
Race condition in the virNetServerClientStartKeepAlive function in libvirt before 1.2.1 allows remote attackers to cause a denial of service (libvirtd crash) by closing a connection before a keepalive response is sent.