SB20261103103 - Ubuntu update for linux, linux-aws, linux-fips and more



SB20261103103 - Ubuntu update for linux, linux-aws, linux-fips and more

Published: November 3, 2026

Security Bulletin ID SB20261103103
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 2
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

Medium 50% Low 50%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 2 vulnerabilities.


1) Improper Resource Shutdown or Release (CVE-ID: CVE-2021-28714)

CWE-ID: CWE-404 - Improper Resource Shutdown or Release

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. A remote user can use a UDP connection on a fast interface to trigger resource exhaustion and perform a denial of service (DoS) attack.


2) Use-after-free (CVE-ID: CVE-2021-3640)

CWE-ID: CWE-416 - Use After Free

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 use-after-free error in sco_sock_sendmsg() function of the Linux kernel HCI subsystem. A privileged local user can call ioct UFFDIO_REGISTER or other way trigger race condition to escalate privileges on the system.


Remediation

Install update from vendor's website.