CVE-2025-40139: Linux

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: smc: Use __sk_dst_get() and dst_dev_rcu() in in smc_clc_prfx_set(). smc_clc_prfx_set() is called during connect() and not under RCU nor RTNL. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dev_dst_rcu() under rcu_read_lock() after kernel_getsockname(). Note that the returned value of smc_clc_prfx_set() is not used in the caller. While at it, we change the 1st arg of smc_clc_prfx_set[46]_rcu() not to touch dst there.

Affected products

• Linux Linux: from 4.11, before 6.1.187 (fixed in 6.1.187); from 6.2, before 6.6.156 (fixed in 6.6.156); from 6.7, before 6.12.108 (fixed in 6.12.108); from 6.13, before 6.17.3 (fixed in 6.17.3)

Published 2025-11-12. Last modified 2026-09-02.