CVE-2026-72057

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: preserve tc_skb_cb across defragmentation tcf_ct_handle_fragments() calls nf_ct_handle_fragments() without saving and restoring skb->cb. The defrag helper clears IPCB/IP6CB, which aliases the tc_skb_cb/qdisc_skb_cb control buffer. Fragmented traffic through act_ct therefore loses qdisc metadata such as pkt_segs and can trigger WARN_ON_ONCE() in qdisc_pkt_segs() when panic_on_warn is enabled. Save and restore the full tc_skb_cb around nf_ct_handle_fragments(), matching the pattern used by ovs_ct_handle_fragments().

References

• https://git.kernel.org/stable/c/2400c4b05d58834b994500a9eec90a37db44187c
• https://git.kernel.org/stable/c/5c3ae5f6c7c6de73ea9b6a75154fe4ed343e1bac
• https://git.kernel.org/stable/c/9092e15defbe6c7bc241c306093ca9d358a578e7
• https://git.kernel.org/stable/c/b3d835407846134b0d54637c0281b39bebef831d
• https://git.kernel.org/stable/c/f7f45ceb855d9ba1cba594fb3f383255f7013fad