CVE-2026-72057
HighCVSS 8.2Exploitation Probability (EPSS)
Low risk44th percentile - higher than 44% of all known CVEs
Summary
In the Linux kernel, the act_ct module's tcf_ct_handle_fragments() does not save and restore skb->cb during defragmentation. This causes loss of qdisc metadata like pkt_segs and can trigger WARN_ON_ONCE(). Added save and restore of tc_skb_cb.
Risk Assessment
Risk of packet metadata loss and potential system crashes due to kernel warnings, especially with panic_on_warn enabled.
Recommendation
It is recommended to update the Linux kernel to a version containing the fix that preserves tc_skb_cb during defragmentation.
Original NVD description (English source)
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().