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UBUNTU-CVE-2026-15705

usbredir: fix use-after-free on buffered bulk packet overflow

UBUNTU-CVE-2026-15578

QEMU VNC Tight PNG channel-max truncation causes remote denial of service

Qemu-kvm: qemu-guest-agent: local privilege escalation via symlink attack in guest-ssh-add-authorized-keys

A flaw was found in the QEMU Guest Agent (qga). A local unprivileged user can exploit a vulnerability in the guest-ssh-add-authorized-keys command handler by manipulating symbolic links. This can occur either through a deterministic directory-symlink bypass or a Time-of-Check to Time-of-Use (TOCTOU) file-symlink race. Successful exploitation allows the attacker to gain ownership of arbitrary root-owned files or directories, leading to root access. This vulnerability requires an external management layer (e.g., libvirt) to trigger the affected code path.

Qemu-kvm: hyperv/syndbg: missing mapped-length guard after cpu_physical_memory_map causes host oob write

A flaw was found in QEMU. This vulnerability allows a local attacker within a guest virtual machine to write data beyond its allocated memory. This occurs when cpu_physical_memory_map() returns a shorter length than expected, leading to an out-of-bounds write. Successful exploitation could result in unauthorized access to guest memory or corruption of heap-allocated objects, potentially causing information disclosure, data integrity issues, or a denial of service.

UBUNTU-CVE-2026-8343

ui: fix validation of VNC extended clipboard data length

UBUNTU-CVE-2026-6425

libvhost-user: fix buffer overflow in virtqueue_read_indirect_desc()

UBUNTU-CVE-2026-48004

9pfs: fix missing rename lock in v9fs_co_readdir_many

UBUNTU-CVE-2026-48003

ui/vnc: fix OOB read updating VNC update frequency stats

UBUNTU-CVE-2026-48002

ui/vnc OOB writes

qemu regression

USN-8412-1 fixed vulnerabilities QEMU. On Ubuntu 20.04 LTS, the fix for CVE-2024-4467 was incomplete and prevented the creation of boot volumes from qcow2 images. This update fixes the problem. We apologize for the inconvenience. Original advisory details: Felipe Franciosi, Raphael Norwitz, and Peter Turschmid discovered that the iSCSI block driver in QEMU incorrectly handled certain responses from an iSCSI server. A remote attacker could possibly use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS. (CVE-2020-1711) It was discovered th

• Обновитесь до 1:4.2-3ubuntu6.30+esm3

Qemu-kvm: heap buffer overflow in virtio-blk scsi request handling

A flaw was found in QEMU's virtio-blk device. The issue arises because the device does not properly validate the size of input descriptors before writing data. A malicious guest with high privileges could exploit this vulnerability by submitting a malformed virtio-blk SCSI request, leading to an out-of-bounds write in the host heap memory and a potential denial of service (DoS) for the QEMU process.

UBUNTU-CVE-2026-5763

[virtio-scsi request size mismatch]

UBUNTU-CVE-2026-3890

[hcd-ohci: infinite loop]

Qemu-kvm: heap buffer out-of-bounds read in vmdk compressed grain parsing

A flaw was found in QEMU. A specially crafted VMDK image could trigger an out-of-bounds read vulnerability, potentially leading to a 12-byte leak of sensitive information or a denial of service condition (DoS).

• Обновитесь до 1:4.2-3ubuntu6.30+esm1

Qemu-kvm: vnc websocket handshake use-after-free

A flaw was found in QEMU. If the QIOChannelWebsock object is freed while it is waiting to complete a handshake, a GSource is leaked. This can lead to the callback firing later on and triggering a use-after-free in the use of the channel. This can be abused by a malicious client with network access to the VNC WebSocket port to cause a denial of service during the WebSocket handshake prior to the VNC client authentication.

• Обновитесь до 1:4.2-3ubuntu6.30+esm1

Qemu: sdhci: heap buffer overflow in sdhci_write_dataport()

A heap-based buffer overflow was found in the SDHCI device emulation of QEMU. The bug is triggered when both `s->data_count` and the size of `s->fifo_buffer` are set to 0x200, leading to an out-of-bound access. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition.

• Обновитесь до 1:4.2-3ubuntu6.30+esm1

Qemu: scsi: lsi53c895a: use-after-free local privilege escalation vulnerability

A use-after-free vulnerability was found in the QEMU LSI53C895A SCSI Host Bus Adapter emulation. This issue can lead to a crash or VM escape.

• Обновитесь до 1:4.2-3ubuntu6.30+esm1

Qemu-kvm: information leak in virtio devices

A flaw was found in QEMU, in the virtio-scsi, virtio-blk, and virtio-crypto devices. The size for virtqueue_push as set in virtio_scsi_complete_req / virtio_blk_req_complete / virito_crypto_req_complete could be larger than the true size of the data which has been sent to guest. Once virtqueue_push() finally calls dma_memory_unmap to ummap the in_iov, it may call the address_space_write function to write back the data. Some uninitialized data may exist in the bounce.buffer, leading to an information leak.

Qemu-kvm: usb: assertion failure in usb_ep_get()

A flaw was found in QEMU. An assertion failure was present in the usb_ep_get() function in hw/net/core.c when trying to get the USB endpoint from a USB device. This flaw may allow a malicious unprivileged guest user to crash the QEMU process on the host and cause a denial of service condition.

• Обновитесь до 1:4.2-3ubuntu6.30+esm1

Qemu: denial of service via improper synchronization in qemu nbd server during socket closure

A flaw was found in the QEMU NBD Server. This vulnerability allows a denial of service (DoS) attack via improper synchronization during socket closure when a client keeps a socket open as the server is taken offline.

• Обновитесь до 1:4.2-3ubuntu6.30+esm2