The virConnectBaselineHypervisorCPU() and virConnectCompareHypervisorCPU() libvirt APIs, 4.x.x before 4.10.1 and 5.x.x before 5.4.1, accept an "emulator" argument to specify the program providing emulation for a domain. Since v1.2.19, libvirt will execute that program to probe the domain's capabilities. Read-only clients could specify an arbitrary path for this argument, causing libvirtd to execute a crafted executable with its own privileges.

The virConnectGetDomainCapabilities() libvirt API, versions 4.x.x before 4.10.1 and 5.x.x before 5.4.1, accepts an "emulatorbin" argument to specify the program providing emulation for a domain. Since v1.2.19, libvirt will execute that program to probe the domain's capabilities. Read-only clients could specify an arbitrary path for this argument, causing libvirtd to execute a crafted executable with its own privileges.

It was discovered that libvirtd, versions 4.x.x before 4.10.1 and 5.x.x before 5.4.1, would permit readonly clients to use the virDomainManagedSaveDefineXML() API, which would permit them to modify managed save state files. If a managed save had already been created by a privileged user, a local attacker could modify this file such that libvirtd would execute an arbitrary program when the domain was resumed.