CVE-2026-72057: Linux

High severity, CVSS 8.2. EPSS: 0.6% chance of exploitation in the next 30 days.

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().

Affected products

• Linux Linux: from 5.15.13, before 5.15.217 (fixed in 5.15.217); from 5.16, before 6.1.184 (fixed in 6.1.184); from 6.2, before 6.6.145 (fixed in 6.6.145); from 6.7, before 6.12.97 (fixed in 6.12.97); from 6.13, before 6.18.40 (fixed in 6.18.40); from 6.19, before 7.1.5 (fixed in 7.1.5)

Published 2026-08-15. Last modified 2026-08-23.