CVE-2021-3527

A flaw was found in the USB redirector device (usb-redir) of QEMU. Small USB packets are combined into a single, large transfer request, to reduce the overhead and improve performance. The combined size of the bulk transfer is used to dynamically allocate a variable length array (VLA) on the stack without proper validation. Since the total size is not bounded, a malicious guest could use this flaw to influence the array length and cause the QEMU process to perform an excessive allocation on the stack, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

This issue affects the version of qemu-kvm as shipped with Red Hat Enterprise Linux 8 and Red Hat Enterprise Linux 8 Advanced Virtualization. A future update may address this flaw.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.