BaseFortify

Publication date: 2025-11-12

Last updated on: 2025-11-12

Assigner: kernel.org

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.

CVSS Scores

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Meta Information

Published

2025-11-12

Last Modified

2025-11-12

Generated

2026-07-06

AI Q&A

2025-11-13

EPSS Evaluated

2026-07-04

NVD

CVE-2025-40139

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves improper handling of socket destination references in the smc_clc_prfx_set() function. The function was using sk_dst_get(sk)->dev without proper synchronization, which could trigger a use-after-free (UAF) condition. The fix involves using __sk_dst_get() and dev_dst_rcu() under rcu_read_lock() to safely access the destination device, preventing the UAF.

Impact Analysis

The vulnerability could lead to a use-after-free condition in the Linux kernel networking code, potentially causing kernel crashes or allowing an attacker to execute arbitrary code with kernel privileges, leading to system compromise.

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