HighFix available
net/sched: act_ct: preserve tc_skb_cb across defragmentation
Type: advisorySources: OSV
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().
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.15.217, 6.1.184, 6.12.97, 6.18.40, 6.6.145, 7.1.5
- CVEs
- CVE-2026-72057
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 14:05 UTC · Revision 1
Source evidence
net/sched: act_ct: preserve tc_skb_cb across defragmentation
core-osv · Original sourcePublished 15 Aug 2026, 05:52 UTC
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().
osv:CVE-2026-72057
Kernel
Fixed versions: 5.15.217, 6.1.184, 6.6.145, 6.12.97, 6.18.40, 7.1.5
Complete source record
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