CVE-2026-72057
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 versions
Linux kernel versions
5.15.13,
5.16
and later are affected. Fixed in
6.6.145,
6.12.97,
6.18.40,
7.1.5,
7.2-rc1
and their respective stable series.
References
5 totalFrequently asked questions
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What is CVE-2026-72057?
CVE-2026-72057 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.15.13 onward and has been patched in 6.6.145, 6.12.97, 6.18.40 and others. CVE-2026-72057 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-72057?
Yes. CVE-2026-72057 has been patched. Fixed versions include 6.6.145, 6.12.97, 6.18.40 and others. If you are running Linux kernel 5.15.13 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-72057 actively exploited?
No. CVE-2026-72057 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.