CVE-2025-40168: smc: Use __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match().

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-11-12 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: smc: Use __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match(). smc_clc_prfx_match() is called from smc_listen_work() and not under RCU nor RTNL. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dst_dev_rcu(). Note that the returned value of smc_clc_prfx_match() is not used in the caller.

Affected products

Linux kernel: 4.11 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/235f81045c008169cc4e1955b4a64e118eebe61b
https://git.kernel.org/stable/c/326e5cf301d0bec0a672aa834d8254c4f9df6255
https://git.kernel.org/stable/c/3f119c37aa293af41400cccb3d89fab8dcf774b0
https://git.kernel.org/stable/c/4f5f52a5842937f945582a93cb9daed9ea526fee
https://git.kernel.org/stable/c/d26e80f7fb62d77757b67a1b94e4ac756bc9c658

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