CVE-2026-72057: net/sched: act_ct: preserve tc_skb_cb across defragmentation
In the Linux kernel, the following vulnerability has been resolved:
net/sched: actct: preserve tcskbcb across defragmentation
tcfcthandlefragments() calls nfcthandlefragments() without saving and restoring skb->cb. The defrag helper clears IPCB/IP6CB, which aliases the tcskbcb/qdiscskbcb control buffer. Fragmented traffic through actct therefore loses qdisc metadata such as pktsegs and can trigger WARNONONCE() in qdiscpktsegs() when paniconwarn is enabled.
Save and restore the full tcskbcb around nfcthandlefragments(), matching the pattern used by ovscthandlefragments().
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72057?
CVE-2026-72057 has a risk score of 17, indicating a high level of severity.
What does CVE-2026-72057 affect?
CVE-2026-72057 affects the Linux kernel, specifically the handling of defragmentation in network scheduling.
How do I fix CVE-2026-72057?
To fix CVE-2026-72057, you need to update your Linux kernel to the latest version where the vulnerability has been resolved.
What could happen if I don't address CVE-2026-72057?
Failure to address CVE-2026-72057 could lead to potential data integrity issues and performance degradation in network operations.
What is the impact of CVE-2026-72057 on system security?
CVE-2026-72057 poses a risk to system security by potentially allowing improper handling of packet data, which could be exploited by attackers.