What’s Vulnerable › Vulnerabilities

CVE-2025-40139: smc: Use __sk_dst_get() and dst_dev_rcu() in in smc_clc_prfx_set().

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% 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 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 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/0736993bfe5c7a9c744ae3fac62d769dfdae54e1
• https://git.kernel.org/stable/c/5a2fccc4b32c13ddde3676f9e15e1a9baa7d6fde
• https://git.kernel.org/stable/c/80d1fd39f4e37d836655e9f7ffccaf78925049bf
• https://git.kernel.org/stable/c/935d783e5de9b64587f3adb25641dd8385e64ddb
• https://git.kernel.org/stable/c/956c57daba55cf9ed25d9f2512883b8a1a927599

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