CVE-2023-32233

2023-05-0817:21:57

redhat.com

access.redhat.com

199

7.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

4.3 Medium

CVSS2

Access Vector

LOCAL

Access Complexity

LOW

Authentication

SINGLE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:L/AC:L/Au:S/C:P/I:P/A:P

0.0004 Low

EPSS

Percentile

5.2%

JSON

A use-after-free vulnerability was found in the Netfilter subsystem of the Linux kernel when processing batch requests to update nf_tables configuration. This vulnerability can be abused to perform arbitrary reads and writes in kernel memory. A local user (with CAP_NET_ADMIN capability) could use this flaw to crash the system or potentially escalate their privileges on the system.

Mitigation

1. This flaw can be mitigated by preventing the affected netfilter (nf_tables) kernel module from being loaded. For instructions on how to blacklist a kernel module, please see <https://access.redhat.com/solutions/41278>.

2. If the module cannot be disabled, on non-containerized deployments of Red Hat Enterprise Linux, the mitigation is to disable user namespaces:

# echo "user.max_user_namespaces=0" &gt; /etc/sysctl.d/userns.conf  
# sysctl -p /etc/sysctl.d/userns.conf

On containerized deployments, such as Red Hat OpenShift Container Platform, do not use the second mitigation (disabling user namespaces) as the functionality is needed to be enabled. The first mitigation (blacklisting nf_tables) is still viable for containerized deployments, providing the environment is not using netfilter.