CVE-2023-4208 Use-after-free in Linux kernel's net/sched: cls_u32 component
A use-after-free in the Linux kernel's cls_u32 component allows local attackers to escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-4208?
CVE-2023-4208 is a high-severity use after free vulnerability in Debian Debian Linux, published on 6 Sep 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation.
When u32_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.
We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.
Weakness: CWE-416
Which versions are affected by CVE-2023-4208?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2023-4208?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2023-4208 being exploited?
There is no known exploitation of CVE-2023-4208 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-28677, DEBIAN-CVE-2023-4208, GHSA-ph8p-rrmj-8gf2, UBUNTU-CVE-2023-4208.