SB2021042828 - Red Hat Enterprise Linux 7.6 update for kernel
Published: April 28, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 secuirty vulnerabilities.
1) Use-after-free (CVE-ID: CVE-2020-15436)
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)
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)
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)
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)
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.