A flaw was found in the 9p passthrough filesystem (9pfs) implementation in QEMU. When a local user in the guest writes an executable file with SUID or SGID, none of these privileged bits are correctly dropped. As a result, in rare circumstances, this flaw could be used by malicious users in the guest to elevate their privileges within the guest and help a host local user to elevate privileges on the host.
A flaw was found in the QEMU built-in VNC server. When a client connects to the VNC server, QEMU checks whether the current number of connections crosses a certain threshold and if so, cleans up the previous connection. If the previous connection happens to be in the handshake phase and fails, QEMU cleans up the connection again, resulting in a NULL pointer dereference issue. This could allow a remote unauthenticated client to cause a denial of service.
A flaw was found in the QEMU Guest Agent service for Windows. A local unprivileged user may be able to manipulate the QEMU Guest Agent's Windows installer via repair custom actions to elevate their privileges on the system.
A flaw was found in the QEMU implementation of VMWare's paravirtual RDMA device. This flaw allows a crafted guest driver to allocate and initialize a huge number of page tables to be used as a ring of descriptors for CQ and async events, potentially leading to an out-of-bounds read and crash of QEMU.
A vulnerability in the lsi53c895a device affects the latest version of qemu. A DMA-MMIO reentrancy problem may lead to memory corruption bugs like stack overflow or use-after-free.
An out-of-bounds read flaw was found in the QXL display device emulation in QEMU. The qxl_phys2virt() function does not check the size of the structure pointed to by the guest physical address, potentially reading past the end of the bar space into adjacent pages. A malicious guest user could use this flaw to crash the QEMU process on the host causing a denial of service condition.
An integer overflow and buffer overflow issues were found in the ACPI Error Record Serialization Table (ERST) device of QEMU in the read_erst_record() and write_erst_record() functions. Both issues may allow the guest to overrun the host buffer allocated for the ERST memory device. A malicious guest could use these flaws to crash the QEMU process on the host.
An off-by-one read/write issue was found in the SDHCI device of QEMU. It occurs when reading/writing the Buffer Data Port Register in sdhci_read_dataport and sdhci_write_dataport, respectively, if data_count == block_size. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition.
An integer underflow issue was found in the QEMU VNC server while processing ClientCutText messages in the extended format. A malicious client could use this flaw to make QEMU unresponsive by sending a specially crafted payload message, resulting in a denial of service.
QEMU before 2.0.0 block drivers for CLOOP, QCOW2 version 2 and various other image formats are vulnerable to potential memory corruptions, integer/buffer overflows or crash caused by missing input validations which could allow a remote user to execute arbitrary code on the host with the privileges of the QEMU process.