Qemu : Security Vulnerabilities, CVEs, CVSS score between 7 and 7.99

A bug in QEMU could cause a guest I/O operation otherwise addressed to an arbitrary disk offset to be targeted to offset 0 instead (potentially overwriting the VM's boot code). This could be used, for example, by L2 guests with a virtual disk (vdiskL2) stored on a virtual disk of an L1 (vdiskL1) hypervisor to read and/or write data to LBA 0 of vdiskL1, potentially gaining control of L1 at its next reboot.

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 9p passthrough filesystem (9pfs) implementation in QEMU. The 9pfs server did not prohibit opening special files on the host side, potentially allowing a malicious client to escape from the exported 9p tree by creating and opening a device file in the shared folder.

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 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 virtio-net device of QEMU. This flaw was inadvertently introduced with the fix for CVE-2021-3748, which forgot to unmap the cached virtqueue elements on error, leading to memory leakage and other unexpected results. Affected QEMU version: 6.2.0.

A DMA reentrancy issue was found in the Tulip device emulation in QEMU. When Tulip reads or writes to the rx/tx descriptor or copies the rx/tx frame, it doesn't check whether the destination address is its own MMIO address. This can cause the device to trigger MMIO handlers multiple times, possibly leading to a stack or heap overflow. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition.

A flaw was found in the QEMU virtio-fs shared file system daemon (virtiofsd) implementation. This flaw is strictly related to CVE-2018-13405. A local guest user can create files in the directories shared by virtio-fs with unintended group ownership in a scenario where a directory is SGID to a certain group and is writable by a user who is not a member of the group. This could allow a malicious unprivileged user inside the guest to gain access to resources accessible to the root group, potentially escalating their privileges within the guest. A malicious local user in the host might also leverage this unexpected executable file created by the guest to escalate their privileges on the host system.

A race condition flaw was found in the 9pfs server implementation of QEMU up to and including 5.2.0. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.

A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non direct access region, due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU, resulting in a denial of service condition, or potentially execute code on the host with the privileges of the QEMU process.

An out-of-bounds write flaw was found in the UAS (USB Attached SCSI) device emulation of QEMU in versions prior to 6.2.0-rc0. The device uses the guest supplied stream number unchecked, which can lead to out-of-bounds access to the UASDevice->data3 and UASDevice->status3 fields. A malicious guest user could use this flaw to crash QEMU or potentially achieve code execution with the privileges of the QEMU process on the host.

tftp.c in libslirp 4.1.0, as used in QEMU 4.2.0, does not prevent ..\ directory traversal on Windows.

An out-of-bounds heap buffer access flaw was found in the way the iSCSI Block driver in QEMU versions 2.12.0 before 4.2.1 handled a response coming from an iSCSI server while checking the status of a Logical Address Block (LBA) in an iscsi_co_block_status() routine. A remote user could use this flaw to crash the QEMU process, resulting in a denial of service or potential execution of arbitrary code with privileges of the QEMU process on the host.

An issue was discovered in ide_dma_cb() in hw/ide/core.c in QEMU 2.4.0 through 4.2.0. The guest system can crash the QEMU process in the host system via a special SCSI_IOCTL_SEND_COMMAND. It hits an assertion that implies that the size of successful DMA transfers there must be a multiple of 512 (the size of a sector). NOTE: a member of the QEMU security team disputes the significance of this issue because a "privileged guest user has many ways to cause similar DoS effect, without triggering this assert.

libslirp 4.0.0, as used in QEMU 4.1.0, has a use-after-free in ip_reass in ip_input.c.

qemu-bridge-helper.c in QEMU 3.1 and 4.0.0 does not ensure that a network interface name (obtained from bridge.conf or a --br=bridge option) is limited to the IFNAMSIZ size, which can lead to an ACL bypass.

QEMU 3.0.0 has an Integer Overflow because the qga/commands*.c files do not check the length of the argument list or the number of environment variables. NOTE: This has been disputed as not exploitable

interface_release_resource in hw/display/qxl.c in QEMU 3.1.x through 4.0.0 has a NULL pointer dereference.

In QEMU 3.0.0, tcp_emu in slirp/tcp_subr.c has a heap-based buffer overflow.

hw/sparc64/sun4u.c in QEMU 3.1.50 is vulnerable to a NULL pointer dereference, which allows the attacker to cause a denial of service via a device driver.

QEMU can have an infinite loop in hw/rdma/vmw/pvrdma_dev_ring.c because return values are not checked (and -1 is mishandled).

hw/rdma/vmw/pvrdma_main.c in QEMU does not implement a read operation (such as uar_read by analogy to uar_write), which allows attackers to cause a denial of service (NULL pointer dereference).

hw/rdma/vmw/pvrdma_cmd.c in QEMU allows attackers to cause a denial of service (NULL pointer dereference or excessive memory allocation) in create_cq_ring or create_qp_rings.

Qemu has a Buffer Overflow in pcnet_receive in hw/net/pcnet.c because an incorrect integer data type is used.

Qemu has a Buffer Overflow in rtl8139_do_receive in hw/net/rtl8139.c because an incorrect integer data type is used.