What is CVE-2025-40139?

CVE-2025-40139 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, affecting Linux kernel versions from 4.11 onward and patched in 6.1.187, 6.6.156, 6.12.108 and others. CVE-2025-40139 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-40139?

CVE-2025-40139 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2025-40139?

Yes, CVE-2025-40139 has been patched. Fixed versions include 6.1.187, 6.6.156, 6.12.108 and others. If you are running Linux kernel 4.11 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-40139 actively exploited?

CVE-2025-40139 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-40139

High

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.

Package Linux Kernel

Published 2025-11-12

Last modified 2026-09-02

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 4.11 and later are affected. Fixed in 6.1.187, 6.6.156, 6.12.108, 6.17.3, 6.18 and their respective stable series.

Affected from

≥ 4.11

Fixed in

✓ 6.1.187 6.1.x ✓ 6.6.156 6.6.x ✓ 6.12.108 6.12.x ✓ 6.17.3 6.17.x ✓ 6.18

References

5 total

Details

CVE ID CVE-2025-40139

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2025-11-12

Modified 2026-09-02

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-40139?

CVE-2025-40139 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 4.11 onward and has been patched in 6.1.187, 6.6.156, 6.12.108 and others. CVE-2025-40139 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-40139?

CVE-2025-40139 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2025-40139?

Yes. CVE-2025-40139 has been patched. Fixed versions include 6.1.187, 6.6.156, 6.12.108 and others. If you are running Linux kernel 4.11 or later up to the fix versions, apply the relevant patch for your kernel branch.
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.