Linux Kernel Reference Leak Vulnerability in Net/Sched Act_Ct Component

A reference leak vulnerability has been identified in the Linux kernel's net/sched component, specifically within the act_ct functionality. This issue arises when switching zones or network namespaces without clearing the connection tracking (ct) data in between, leading to a leak of the old ct entry reference. The problem occurs because the function tcf_ct_skb_nfct_cached() returns false, allowing tcf_ct_flow_table_lookup() to overwrite the ct entry. The vulnerability affects several different versions and/or ranges of the Linux kernel.

Impact

Exploitation of this vulnerability can lead to a reference leak, causing improper management of connection tracking data when switching network zones or namespaces.

Remediation

The vulnerability has been fixed in the official Linux Git repository. Users should upgrade to the latest version.