Amazon Linux AMI 2: CVE-2023-4207: Security patch for kernel, kernel-livepatch-4.14.320-243.544, kernel-livepatch-4.14.322-244.536, kernel-livepatch-4.14.322-244.539, kernel-livepatch-4.14.322-246.539, kernel-livepatch-5.10.186-179.751 (Multiple Advisories)

A use-after-free vulnerability in the Linux kernel's net/sched: cls_fw component can be exploited to achieve local privilege escalation.

When fw_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 76e42ae831991c828cffa8c37736ebfb831ad5ec.