CVE-2025-40133: Linux

High severity, CVSS 8.1. EPSS: 0.5% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable(). mptcp_active_enable() is called from subflow_finish_connect(), which is icsk->icsk_af_ops->sk_rx_dst_set() and it's not always under RCU. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dst_dev_rcu().

Affected products

• Linux Linux: from 6.12, before 6.12.55 (fixed in 6.12.55); from 6.13, before 6.17.3 (fixed in 6.17.3)

Published 2025-11-12. Last modified 2026-07-30.