Cloud Hypervisor is a Virtual Machine Monitor for Cloud workloads. Versions 34.0 through 50.0 arevulnerable to arbitrary host file exfiltration (constrained by process privileges) when using virtio-block devices backed by raw images. A malicious guest can overwrite its disk header with a crafted QCOW2 structure pointing to a sensitive host path. Upon the next VM boot or disk scan, the image format auto-detection parses this header and serves the host file's contents to the guest. Guest-initiated VM reboots are sufficient to trigger a disk scan and do not cause the Cloud Hypervisor process to exit. Therefore, a single VM can perform this attack without needing interaction from the management stack. Successful exploitation requires the backing image to be either writable by the guest or sourced from an untrusted origin. Deployments utilizing only trusted, read-only images are not affected. This issue has been fixed in version 50.1. To workaround, enable land lock sandboxing and restrict process privileges and access.

Cloud hypervisor is a Virtual Machine Monitor for Cloud workloads. This vulnerability allows users to close arbitrary open file descriptors in the Cloud Hypervisor process via sending malicious HTTP request through the HTTP API socket. As a result, the Cloud Hypervisor process can be easily crashed, causing Deny-of-Service (DoS). This can also be a potential Use-After-Free (UAF) vulnerability. Users require to have the write access to the API socket file to trigger this vulnerability. Impacted versions of Cloud Hypervisor include upstream main branch, v31.0, and v30.0. The vulnerability was initially detected by our httpapifuzzer via oss-fuzz. This issue has been addressed in versions 30.1 and 31.1. Users unable to upgrade may mitigate this issue by ensuring the write access to the API socket file is granted to trusted users only.