SB2021042828 - Red Hat Enterprise Linux 7.6 update for kernel

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Main Vulnerability Database SB2021042828

SB2021042828 - Red Hat Enterprise Linux 7.6 update for kernel

Published: April 28, 2021

Security Bulletin ID SB2021042828
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 5
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

Medium 20% Low 80%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 5 vulnerabilities.


1) Use-after-free (CVE-ID: CVE-2020-15436)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 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/E:U/U:Clear


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

The vulnerability exists due to a use-after-free error in fs/block_dev.c in the Linux kernel. A local user can run a specially crafted program to escalate privileges on the system.


2) Path traversal (CVE-ID: CVE-2020-28374)

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote user to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in drivers/target/target_core_xcopy.c in the Linux kernel. A remote user with access to iSCSI LUN can send a specially crafted XCOPY request and read or write arbitrary files on the system.



3) Information disclosure (CVE-ID: CVE-2021-27363)

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


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

The vulnerability exists due to the show_transport_handle() shows iSCSI transport handle to non-root users. A local user can gain unauthorized access to sensitive information and use it along with another vulnerability, such as #VU51452, to escalate privileges on the system.


4) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-27364)

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

CVSSv4: 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/E:U/U:Clear


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

The vulnerability exists due to iscsi_if_recv_msg() allows non-root users to connect and send commands to the Linux kernel. A local user can escalate privileges on the system.


5) Buffer overflow (CVE-ID: CVE-2021-27365)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: 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/E:U/U:Clear


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

The vulnerability exists due to a boundary error when processing Netlink messages in Linux kernel through 5.11.3, as certain iSCSI data structures do not have appropriate length constraints or checks, and can exceed the PAGE_SIZE value. A local unprivileged user can send a Netlink message that is associated with iSCSI, and has a length up to the maximum length of a Netlink message, trigger memory corruption and execute arbitrary code on the system with elevated privileges.


Remediation

Install update from vendor's website.

References