SB2021102147 - Ubuntu update for linux-azure-5.8
Published: October 21, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 9 secuirty vulnerabilities.
1) Out-of-bounds read (CVE-ID: CVE-2019-19449)
The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.
In the Linux kernel 5.0.21, mounting a crafted f2fs filesystem image can lead to slab-out-of-bounds read access in f2fs_build_segment_manager in fs/f2fs/segment.c, related to init_min_max_mtime in fs/f2fs/segment.c (because the second argument to get_seg_entry is not validated).
2) Protection Mechanism Failure (CVE-ID: CVE-2020-26541)
The vulnerability allows a local user to escalate privileges on the system.
The Linux kernel through 5.8.13 does not properly enforce the Secure
Boot Forbidden Signature Database (aka dbx) protection mechanism. This
affects certs/blacklist.c and certs/system_keyring.c. A local user can escalate privileges on the system.
3) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-36311)
The vulnerability allows a local user to perform a denial of service attack.
The vulnerability exists due to an error in arch/x86/kvm/svm/sev.c in Linux kernel, which allows soft lockup by triggering destruction of a large SEV VM (which requires unregistering many encrypted regions).
4) Buffer overflow (CVE-ID: CVE-2021-22543)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error in Linux kernel when handling VM_IO|VM_PFNMAP vmas in KVM. A local user can can bypass RO checks and cause the pages to get freed while still accessible by the VMM and guest. As a result, an attacker with the ability to start and control a VM to read/write random pages of memory, can trigger memory corruption and execute arbitrary code with elevated privileges.
5) Out-of-bounds write (CVE-ID: CVE-2021-3612)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error in joystick devices subsystem in Linux kernel. A local user can make a specially crafted JSIOCSBTNMAP IOCTL call, trigger out-of-bounds write and execute arbitrary code with escalated privileges.
6) Resource exhaustion (CVE-ID: CVE-2021-3759)
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists in the Linux kernel’s ipc functionality of the memcg subsystem when user calls the semget function multiple times, creating semaphores. A local user can trigger resource exhaustion and perform a denial of service (DoS) attack.
7) Race condition (CVE-ID: CVE-2021-38199)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to fs/nfs/nfs4client.c in the Linux kernel has incorrect connection-setup ordering. A remote attacker with access to a remote NFSv4 server can perform a denial of service (DoS) attack by arranging the server to be unreachable during trunking detection.
8) Buffer overflow (CVE-ID: CVE-2021-38207)
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
drivers/net/ethernet/xilinx/ll_temac_main.c in the Linux kernel before 5.12.13 allows remote attackers to cause a denial of service (buffer overflow and lockup) by sending heavy network traffic for about 10 minutes.
9) Race condition (CVE-ID: CVE-2021-40490)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a race condition in ext4_write_inline_data_end in fs/ext4/inline.c in the ext4 subsystem in the Linux kernel. A local user can exploit the race and gain unauthorized access to sensitive information and escalate privileges on the system.
Remediation
Install update from vendor's website.