SB2021101989 - Ubuntu update for linux, linux-aws, linux-aws-5.11 and more



SB2021101989 - Ubuntu update for linux, linux-aws, linux-aws-5.11 and more

Published: October 19, 2021 Updated: October 31, 2026

Security Bulletin ID SB2021101989
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 8
Exploitation vector Adjecent network
Highest impact Data manipulation

Breakdown by Severity

Medium 13% Low 88%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 8 vulnerabilities.


1) Cryptographic Issues (CVE-ID: CVE-2020-3702)

CWE-ID: CWE-310 - Cryptographic Issues

CVSSv4: 6.3 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:L/SA:N]


The vulnerability allows a remote attacker to gain access top sensitive information.

The vulnerability exists due to improper input validation in WIFI driver(Krook). A remote attacker can temporary disable WPA2 or the WPA/WPA2 mixed-mode encryption and intercept traffic in clear text.


2) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-3732)

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists in the way the user mounts the TmpFS filesystem with OverlayFS. A local user can gain access to hidden files that should not be accessible.


3) NULL pointer dereference (CVE-ID: CVE-2021-3739)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: 6.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to read data or crash the application.

The vulnerability exists due to NULL pointer dereference within the btrfs_rm_device() function in fs/btrfs/volumes.c. A local user can read data or crash the application.


4) Out-of-bounds read (CVE-ID: CVE-2021-3743)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 6.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to perform a denial of service attack.

The vulnerability exists due to a boundary condition in the Qualcomm IPC router protocol in the Linux kernel. A local user can gain access to out-of-bounds memory to leak internal kernel information or perform a denial of service attack.


5) Out-of-bounds read (CVE-ID: CVE-2021-3753)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition in the vt_k_ioctl in drivers/tty/vt/vt_ioctl.c in the Linux kernel. A local user can trigger out-of-bounds read error and read contents of memory on the system.


6) Out-of-bounds read (CVE-ID: CVE-2021-38166)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to execute arbitrary code.

The vulnerability exists due to an out-of-bounds read error within the kvmalloc() function in kernel/bpf/hashtab.c. A local user can execute arbitrary code.


7) Race condition (CVE-ID: CVE-2021-40490)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


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.


8) Out-of-bounds write (CVE-ID: CVE-2021-42008)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error in the decode_data() function in drivers/net/hamradio/6pack.c in the Linux kernel. A local user can send input from a process that has the CAP_NET_ADMIN capability and escalate privileges on the system.


Remediation

Install update from vendor's website.