CVE-2025-40139
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 versions
Linux kernel versions
4.11
and later are affected. Fixed in
6.17.3,
6.18
and their respective stable series.
References
The following references provide additional information about CVE-2025-40139 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/0736993bfe5c7a9c744ae3fac62d769dfdae54e1
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PatchKernel patch commithttps://git.kernel.org/stable/c/935d783e5de9b64587f3adb25641dd8385e64ddb
Frequently asked questions
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What is CVE-2025-40139?
CVE-2025-40139 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 4.11 onward and has been patched in 6.17.3 and 6.18. CVE-2025-40139 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2025-40139?
Yes — CVE-2025-40139 has been patched. Fixed versions include 6.17.3 and 6.18. If you are running Linux kernel 4.11 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2025-40139 actively exploited?
No — CVE-2025-40139 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.