CVE-2023-4208: Use-after-free in Linux kernel's net/sched: cls_u32 component
A use-after-free vulnerability in the Linux kernel's net/sched: clsu32 component can be exploited to achieve local privilege escalation.
When u32change() is called on an existing filter, the whole tcfresult struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcfunbindfilter() is always called on the old instance in the success path, decreasing filtercnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.
We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.
Other sources
Linux Kernel could allow a local authenticated attacker to gain elevated privileges on the system, caused by a use-after-free flaw in the net/sched: clsu32 component. By sending a specially crafted request, an authenticated attacker could exploit this vulnerability to gain elevated privileges.
— IBM
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.197-1Fixed in 5.10.191-1Fixed in 6.1.66-1Fixed in 6.1.69-1Fixed in 6.5.13-1Fixed in 6.6.9-1 - Upgrade
Upgrade
F5 Traffix Systems Signaling Delivery Controllerto a version that resolves this vulnerability.Fixed in 5.2.0 - Upgrade
Upgrade
Linux kernel net/sched: cls_u32to a version that resolves this vulnerability.Patch 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 - Upgrade
Upgrade
Linux kernel net/sched: cls_fwto a version that resolves this vulnerability.Patch 76e42ae831991c828cffa8c37736ebfb831ad5ec - Upgrade
Upgrade
Linux kernel net/sched: cls_routeto a version that resolves this vulnerability.Patch b80b829e9e2c1b3f7aae34855e04d8f6ecaf13c8
Event History
Frequently Asked Questions
What is CVE-2023-4208?
CVE-2023-4208 is a use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component.
How can CVE-2023-4208 be exploited?
CVE-2023-4208 can be exploited to achieve local privilege escalation.
What is the severity of CVE-2023-4208?
The severity of CVE-2023-4208 is high with a CVSS score of 7.8.
Which software is affected by CVE-2023-4208?
Linux Kernel versions up to and including 6.5, Debian Linux 12.0, and specific versions of the linux package from the Debian source are affected by CVE-2023-4208.
How do I fix the CVE-2023-4208 vulnerability?
To fix the CVE-2023-4208 vulnerability, upgrade to Linux Kernel version 6.5.3-1 or apply the provided patches for the specific affected software.