CVE-2026-72057

net/sched: act_ct: preserve tc_skb_cb across defragmentation

State: Published
Severity: 8.2 High
Published: Aug 15, 2026
Updated: Oct 19, 2026
Reserved: Aug 9, 2026

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().

Scores

CVSS	Score	Vector	Source
3.1	8.2 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H	Linux

Weaknesses

CWE-662 Improper Synchronization

Affected Products

Product	Versions
LinuxLinux	0d76daf2013ce1da20eab5e26bd81d983e1c18fb to before fb080b6f54835d5d4d11ce3122800e6f0f6689e6Affected ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before 67d6b00a54446c008f52cf70fc0c2ad0c712f85dAffected ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before 2400c4b05d58834b994500a9eec90a37db44187cAffected ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before 5c3ae5f6c7c6de73ea9b6a75154fe4ed343e1bacAffected ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before b3d835407846134b0d54637c0281b39bebef831dAffected ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before f7f45ceb855d9ba1cba594fb3f383255f7013fadAffected ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before 9092e15defbe6c7bc241c306093ca9d358a578e7Affected 5.15.13 to before 5.15.217Affected
LinuxLinux	5.16Affected before 5.16Not affected 5.15.217 through 5.15.Not affected 6.1.184 through 6.1.Not affected 6.6.145 through 6.6.Not affected 6.12.97 through 6.12.Not affected 6.18.40 through 6.18.Not affected 7.1.5 through 7.1.Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

0d76daf2013ce1da20eab5e26bd81d983e1c18fb to before fb080b6f54835d5d4d11ce3122800e6f0f6689e6Affected
ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before 67d6b00a54446c008f52cf70fc0c2ad0c712f85dAffected
ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before 2400c4b05d58834b994500a9eec90a37db44187cAffected
ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before 5c3ae5f6c7c6de73ea9b6a75154fe4ed343e1bacAffected
ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before b3d835407846134b0d54637c0281b39bebef831dAffected
ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before f7f45ceb855d9ba1cba594fb3f383255f7013fadAffected
ec624fe740b416fb68d536b37fb8eef46f90b5c2 to before 9092e15defbe6c7bc241c306093ca9d358a578e7Affected
5.15.13 to before 5.15.217Affected

LinuxLinux

5.16Affected
before 5.16Not affected
5.15.217 through 5.15.*Not affected
6.1.184 through 6.1.*Not affected
6.6.145 through 6.6.*Not affected
6.12.97 through 6.12.*Not affected
6.18.40 through 6.18.*Not affected
7.1.5 through 7.1.*Not affected
7.2 and laterNot affected

References

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