# CVE-2025-40139

## Summary

- **CVE ID:** CVE-2025-40139
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Nov 12, 2025
- **Last Modified:** Sep 2, 2026

## 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 — Linux (a046d57da19f812216f393e7c535f5858f793ac3)
- Linux — Linux (4.11)
- Linux — Linux (0)
- Linux — Linux (6.17.3)
- Linux — Linux (6.18)
- Linux — Linux (6.1.187)
- Linux — Linux (6.6.156)
- Linux — Linux (6.12.108)

## References

- [CNA](https://git.kernel.org/stable/c/0736993bfe5c7a9c744ae3fac62d769dfdae54e1)
- [CNA](https://git.kernel.org/stable/c/935d783e5de9b64587f3adb25641dd8385e64ddb)
- [CNA](https://git.kernel.org/stable/c/5a2fccc4b32c13ddde3676f9e15e1a9baa7d6fde)
- [CNA](https://git.kernel.org/stable/c/80d1fd39f4e37d836655e9f7ffccaf78925049bf)
- [CNA](https://git.kernel.org/stable/c/956c57daba55cf9ed25d9f2512883b8a1a927599)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.15%
- **EPSS Percentile:** 4.8

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._