Ubuntu Security Advisories

Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory. (CVE-2021-3656) Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory. (CVE-2021-3653) Norbert Slusarek discovered that the CAN broadcast manger (bcm) protocol implementation in the Linux kernel did not properly initialize memory in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2021-34693) Murray McAllister discovered that the joystick device interface in the Linux kernel did not properly validate data passed via an ioctl(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code on systems with a joystick device registered. (CVE-2021-3612) It was discovered that the Virtio console implementation in the Linux kernel did not properly validate input lengths in some situations. A local attacker could possibly use this to cause a denial of service (system crash). (CVE-2021-38160)

It was discovered that Python incorrectly handled certain RFCs. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 16.04 ESM. (CVE-2021-3733) It was discovered that Python incorrectly handled certain server responses. An attacker could possibly use this issue to cause a denial of service. (CVE-2021-3737)

USN-5071-1 fixed vulnerabilities in the Linux kernel for Ubuntu 20.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 20.04 LTS for Ubuntu 18.04 LTS. Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory. (CVE-2021-3656) Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory. (CVE-2021-3653) It was discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not ensure enough processing time was given to perform cleanups of large SEV VMs. A local attacker could use this to cause a denial of service (soft lockup). (CVE-2020-36311) It was discovered that the KVM hypervisor implementation in the Linux kernel did not properly perform reference counting in some situations, leading to a use-after-free vulnerability. An attacker who could start and control a VM could possibly use this to expose sensitive information or execute arbitrary code. (CVE-2021-22543) Murray McAllister discovered that the joystick device interface in the Linux kernel did not properly validate data passed via an ioctl(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code on systems with a joystick device registered. (CVE-2021-3612)

Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory. (CVE-2021-3656) Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory. (CVE-2021-3653) Norbert Slusarek discovered a race condition in the CAN BCM networking protocol of the Linux kernel leading to multiple use-after-free vulnerabilities. A local attacker could use this issue to execute arbitrary code. (CVE-2021-3609)

It was discovered that Qt incorrectly handled certain XBM image files. If a user or automated system were tricked into opening a specially crafted PPM file, a remote attacker could cause Qt to crash, resulting in a denial of service. (CVE-2020-17507) It was discovered that Qt incorrectly handled certain graphics operations. If a user or automated system were tricked into performing certain graphics operations, a remote attacker could cause Qt to crash, resulting in a denial of service. (CVE-2021-38593)

USN-5080-1 fixed several vulnerabilities in Libgcrypt. This update provides the corresponding update for Ubuntu 16.04 ESM. Original advisory details: It was discovered that Libgcrypt incorrectly handled ElGamal encryption. An attacker could possibly use this issue to recover sensitive information.

It was discovered that Libgcrypt incorrectly handled ElGamal encryption. An attacker could possibly use this issue to recover sensitive information.

USN-5078-1 fixed several vulnerabilities in Squashfs-Tools. This update provides the corresponding update for Ubuntu 16.04 ESM. Original advisory details: Etienne Stalmans discovered that Squashfs-Tools mishandled certain malformed SQUASHFS files. An attacker could use this vulnerability to write arbitrary files to the filesystem. (CVE-2021-40153) Richard Weinberger discovered that Squashfs-Tools mishandled certain malformed SQUASHFS files. An attacker could use this vulnerability to write arbitrary files to the filesystem. (CVE-2021-41072)

USN-5079-1 fixed several vulnerabilities in curl. This update provides the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. Original advisory details: Patrick Monnerat discovered that curl incorrectly handled upgrades to TLS. When receiving certain responses from servers, curl would continue without TLS even when the option to require a successful upgrade to TLS was specified. (CVE-2021-22946) Patrick Monnerat discovered that curl incorrectly handled responses received before STARTTLS. A remote attacker could possibly use this issue to inject responses and intercept communications. (CVE-2021-22947)

It was discovered that curl incorrect handled memory when sending data to an MQTT server. A remote attacker could use this issue to cause curl to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2021-22945) Patrick Monnerat discovered that curl incorrectly handled upgrades to TLS. When receiving certain responses from servers, curl would continue without TLS even when the option to require a successful upgrade to TLS was specified. (CVE-2021-22946) Patrick Monnerat discovered that curl incorrectly handled responses received before STARTTLS. A remote attacker could possibly use this issue to inject responses and intercept communications. (CVE-2021-22947)

Richard Weinberger discovered that Squashfs-Tools mishandled certain malformed SQUASHFS files. An attacker could use this vulnerability to write arbitrary files to the filesystem.

USN-5077-1 fixed several vulnerabilities in Apport. This update provides the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. Original advisory details: Maik Münch and Stephen Röttger discovered that Apport incorrectly handled certain information gathering operations. A local attacker could use this issue to gain read access to arbitrary files, possibly containing sensitive information.

Maik Münch and Stephen Röttger discovered that Apport incorrectly handled certain information gathering operations. A local attacker could use this issue to gain read access to arbitrary files, possibly containing sensitive information.

It was discovered that Git allowed newline characters in certain repository paths. An attacker could potentially use this issue to perform cross-protocol requests.

Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory.(CVE-2021-3653) Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory.(CVE-2021-3656) Andy Nguyen discovered that the netfilter subsystem in the Linux kernel contained an out-of-bounds write in its setsockopt() implementation. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.(CVE-2021-22555) It was discovered that the virtual file system implementation in the Linux kernel contained an unsigned to signed integer conversion error. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code.(CVE-2021-33909)

It was discovered that Ghostscript incorrectly handled certain PostScript files. If a user or automated system were tricked into processing a specially crafted file, a remote attacker could possibly use this issue to access arbitrary files, execute arbitrary code, or cause a denial of service.

Multiple security issues were discovered in Firefox. If a user were tricked into opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, bypass mixed content blocking, or execute arbitrary code.

Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory. (CVE-2021-3656) Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory. (CVE-2021-3653) Norbert Slusarek discovered that the CAN broadcast manger (bcm) protocol implementation in the Linux kernel did not properly initialize memory in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2021-34693) Murray McAllister discovered that the joystick device interface in the Linux kernel did not properly validate data passed via an ioctl(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code on systems with a joystick device registered. (CVE-2021-3612) It was discovered that the Virtio console implementation in the Linux kernel did not properly validate input lengths in some situations. A local attacker could possibly use this to cause a denial of service (system crash). (CVE-2021-38160)

Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory. (CVE-2021-3656) Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory. (CVE-2021-3653)

Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory. (CVE-2021-3656) Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory. (CVE-2021-3653) It was discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not ensure enough processing time was given to perform cleanups of large SEV VMs. A local attacker could use this to cause a denial of service (soft lockup). (CVE-2020-36311) It was discovered that the KVM hypervisor implementation in the Linux kernel did not properly perform reference counting in some situations, leading to a use-after-free vulnerability. An attacker who could start and control a VM could possibly use this to expose sensitive information or execute arbitrary code. (CVE-2021-22543) Murray McAllister discovered that the joystick device interface in the Linux kernel did not properly validate data passed via an ioctl(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code on systems with a joystick device registered. (CVE-2021-3612)