CVE-2026-64024
A flaw in the Linux kernel allowed attackers to predict TCP sequence numbers by leaking a stale per‑CPU value. The issue was fixed by moving the value back into the packet’s control block. The vulnerability is now resolved in the kernel source.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel (all versions before the patch that moved tcp_tw_isn back to skb->cb[])
Real-world impact
An attacker could predict the initial sequence number of a TCP connection, enabling them to hijack or inject traffic into that connection.
Why this severity
The CVSS score of 9.4 reflects that the flaw is easily exploitable from the network, requires no user interaction, and gives an attacker the ability to compromise the integrity and availability of TCP sessions.
What to do about it
- 01Upgrade the Linux kernel to a version that includes the patch which moves tcp_tw_isn back into skb->cb[].
NVD-referenced vendor advisory
Timeline
- Jul 19, 2026 · 14d agoPublishedDisclosed and added to the National Vulnerability Database.
- Jul 20, 2026 · 13d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.
- Jul 30, 2026 · 3d agoAdvisory updatedThe NVD record was last revised.