CVE-2025-8860

A flaw was found in QEMU in the uefi-vars virtual device. When the guest writes to register UEFI_VARS_REG_BUFFER_SIZE, the .write callback uefi_vars_write is invoked. The function allocates a heap buffer without zeroing the memory, leaving the buffer filled with residual data from prior allocations. When the guest later reads from register UEFI_VARS_REG_PIO_BUFFER_TRANSFER, the .read callback uefi_vars_read returns leftover metadata or other sensitive process memory from the previously allocated buffer, leading to an information disclosure vulnerability.

The qemu-kvm packages shipped in Red Hat Enterprise Linux and RHEL Advanced Virtualization are not affected by this CVE because they didn't provide support for the UEFI variable service (uefi-vars virtual device).

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.