CVE-2023-23454
First published: Sun Jan 01 2023(Updated: )
An out-of-bounds (OOB) read problem was found in cbq_classify in net/sched/sch_cbq.c in the Linux kernel. This flaw allows a local attacker to cause a denial of service because of type confusion (non-negative numbers can sometimes indicate a TC_ACT_SHOT condition rather than valid classification results). Reference: <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=caa4b35b4317d5147b3ab0fbdc9c075c7d2e9c12">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=caa4b35b4317d5147b3ab0fbdc9c075c7d2e9c12</a>
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel-rt | <0:4.18.0-477.10.1.rt7.274.el8_8 | 0:4.18.0-477.10.1.rt7.274.el8_8 |
| redhat/kernel | <0:4.18.0-477.10.1.el8_8 | 0:4.18.0-477.10.1.el8_8 |
| redhat/kernel | <6.2 | 6.2 |
| Linux Kernel | >=2.6.12<=6.1.4 | |
| Debian Linux | =11.0 | |
| debian/linux | 5.10.223-1 5.10.234-1 6.1.129-1 6.1.128-1 6.12.21-1 6.12.22-1 |
Remedy
The mitigation is to disable unprivileged user namespaces by setting user.max_user_namespaces to 0: ``` # echo "user.max_user_namespaces=0" > /etc/sysctl.d/userns.conf # sysctl -p /etc/sysctl.d/userns.conf ``` It is also possible to prevent the affected code from being loaded by blacklisting the `cbq` kernel module. For instructions on how to blacklist a kernel module, please see https://access.redhat.com/solutions/41278.
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Reference Links
- https://www.cve.org/CVERecord?id=CVE-2023-23454 https://nvd.nist.gov/vuln/detail/CVE-2023-23454 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=caa4b35b4317d5147b3ab0fbdc9c075c7d2e9c12
- https://bugzilla.redhat.com/show_bug.cgi?id=2168297
- https://access.redhat.com/errata/RHSA-2023:2736
- https://access.redhat.com/errata/RHSA-2023:2951
- https://access.redhat.com/security/cve/cve-2023-23454
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=caa4b35b4317d5147b3ab0fbdc9c075c7d2e9c12
- https://lists.debian.org/debian-lts-announce/2023/03/msg00000.html
- https://lists.debian.org/debian-lts-announce/2023/05/msg00006.html
- https://www.debian.org/security/2023/dsa-5324
- https://www.openwall.com/lists/oss-security/2023/01/10/1
- https://www.openwall.com/lists/oss-security/2023/01/10/4
- https://launchpad.net/bugs/cve/CVE-2023-23454
- https://access.redhat.com/errata/RHSA-2024:0412
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-23454
- https://nvd.nist.gov/vuln/detail/CVE-2023-23454
- https://security-tracker.debian.org/tracker/CVE-2023-23454
- https://ubuntu.com/security/CVE-2023-23454
- https://git.kernel.org/linus/caa4b35b4317d5147b3ab0fbdc9c075c7d2e9c12
Frequently Asked Questions
What is the severity of CVE-2023-23454?
CVE-2023-23454 is rated as high severity due to its potential for causing denial of service.
How do I fix CVE-2023-23454?
To mitigate CVE-2023-23454, you should update to the patched versions of the affected Linux kernel versions mentioned in the advisory.
What versions are affected by CVE-2023-23454?
CVE-2023-23454 affects various versions of the Linux kernel, specifically versions prior to 4.18.0-477.10.1 and below 6.2.
Who can exploit CVE-2023-23454?
CVE-2023-23454 can be exploited by a local attacker with the ability to execute code on the affected system.
What systems are impacted by CVE-2023-23454?
CVE-2023-23454 impacts systems running affected versions of the Linux kernel, including distributions like Red Hat and Debian.
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