What is RHSA-2023:4256?

RHSA-2023:4256 is a security advisory published by Red Hat Product Security with High severity. Red Hat Security Advisory: kernel security and bug fix update

Which CVE IDs does RHSA-2023:4256 cover?

RHSA-2023:4256 covers the following CVE IDs: CVE-2023-1281, CVE-2023-32233. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of RHSA-2023:4256?

RHSA-2023:4256 has a CVSS v3 base score of 7.8, published by Red Hat Product Security.

Which products are affected by RHSA-2023:4256?

RHSA-2023:4256 affects 149 products, including: Red Hat Enterprise Linux BaseOS AUS (v.8.4); Red Hat Enterprise Linux BaseOS E4S (v.8.4); Red Hat Enterprise Linux BaseOS TUS (v.8.4); bpftool-0:4.18.0-305.97.1.el8_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4); bpftool-0:4.18.0-305.97.1.el8_4.ppc64le as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4); and others — see the full list on the advisory page.

RHSA-2023:4256HighCVSS 7.8

Red Hat Security Advisory: kernel security and bug fix update

Vendor

Red Hat Product Security

Published

July 25, 2023

Last Modified

July 30, 2026

🔗 CVE IDs covered (2)

CVE-2023-1281 →CVE-2023-32233 →

📋 Description

CVE-2023-1281 — kernel: tcindex: use-after-free vulnerability in traffic control index filter allows privilege escalation CVE-2023-32233 — kernel: netfilter: use-after-free in nf_tables when processing batch requests can lead to privilege escalation

🎯 Affected products149

Red Hat Enterprise Linux BaseOS AUS (v.8.4)
Red Hat Enterprise Linux BaseOS E4S (v.8.4)
Red Hat Enterprise Linux BaseOS TUS (v.8.4)
bpftool-0:4.18.0-305.97.1.el8_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
bpftool-0:4.18.0-305.97.1.el8_4.ppc64le as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
bpftool-0:4.18.0-305.97.1.el8_4.s390x as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
bpftool-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
bpftool-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
bpftool-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS TUS (v.8.4)
bpftool-debuginfo-0:4.18.0-305.97.1.el8_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
bpftool-debuginfo-0:4.18.0-305.97.1.el8_4.ppc64le as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
bpftool-debuginfo-0:4.18.0-305.97.1.el8_4.s390x as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
bpftool-debuginfo-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
bpftool-debuginfo-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
bpftool-debuginfo-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS TUS (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.ppc64le as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.s390x as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.src as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.src as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.src as a component of Red Hat Enterprise Linux BaseOS TUS (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
kernel-0:4.18.0-305.97.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS TUS (v.8.4)
kernel-abi-stablelists-0:4.18.0-305.97.1.el8_4.noarch as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
kernel-abi-stablelists-0:4.18.0-305.97.1.el8_4.noarch as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
kernel-abi-stablelists-0:4.18.0-305.97.1.el8_4.noarch as a component of Red Hat Enterprise Linux BaseOS TUS (v.8.4)
kernel-core-0:4.18.0-305.97.1.el8_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
kernel-core-0:4.18.0-305.97.1.el8_4.ppc64le as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
kernel-core-0:4.18.0-305.97.1.el8_4.s390x as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.4)
+119 more not shown

✅ Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Workaround: This flaw can be mitigated by preventing the affected traffic control index filter (cls_tcindex) kernel module from loading during the boot time, ensure the module is added into the blacklist file. ~~~ Refer: How do I blacklist a kernel module to prevent it from loading automatically? https://access.redhat.com/solutions/41278 ~~~ Workaround: 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" > /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.

🔗 CVE IDs covered (2)

📋 Description

🎯 Affected products149

✅ Remediation

🔗 References (5)