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ubuntuUbuntuLSN-0083-1
HistoryJan 06, 2022 - 12:00 a.m.

Kernel Live Patch Security Notice

2022-01-0600:00:00
ubuntu.com
92
linux kernel
bpf
kvm
amd
avic
hypervisor
vm
memory
hugetlb
tlb
netfilter
out-of-bounds write
setsockopt()
denial of service
system crash
virtual file system
conversion error

CVSS2

7.2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS3

8.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

AI Score

7.6

Confidence

High

EPSS

0.002

Percentile

59.8%

Details

The BPF subsystem in the Linux kernel before 4.17 mishandles
situations with a long jump over an instruction sequence where inner
instructions require substantial expansions into multiple BPF instructions,
leading to an overflow. This affects kernel/bpf/core.c and
net/core/filter.c.(CVE-2018-25020)

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)

Nadav Amit discovered that the hugetlb implementation in the Linux kernel
did not perform TLB flushes under certain conditions. A local attacker
could use this to leak or alter data from other processes that use huge
pages.(CVE-2021-4002)

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)

CVSS2

7.2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS3

8.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

AI Score

7.6

Confidence

High

EPSS

0.002

Percentile

59.8%