Is CVE-2025-40139 in the CISA KEV catalog?

No. CVE-2025-40139 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2025-40139?

CVE-2025-40139 has a CVSS v3 base score of 8.4 (Important).

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

CVE-2025-40139 has an EPSS score of 0.17% (6th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2025-40139?

Upgrade linux on debian unstable to 6.17.6-1 or later. Fixes are available for 46 affected products.

CVE & CISA-KEV Catalog

CVE-2025-40139

HIGH

8.4

CVSS v3

NVD

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.

How to fix

Remediation Available

linuxDebian

Fixed in:6.17.6-1CVE-2025-40139

linuxUbuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-awsUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-azureUbuntu

Fixed in:6.17.0-1008.8USN-8029-3

linux-gcpUbuntu

Fixed in:6.17.0-1007.7USN-8030-1

linux-image-6.17.0-1006-realtimeUbuntu

Fixed in:6.17.0-1006.7USN-8029-1

linux-image-6.17.0-1007-awsUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-6.17.0-1007-aws-64kUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-6.17.0-1007-gcpUbuntu

Fixed in:6.17.0-1007.7USN-8030-1

linux-image-6.17.0-1007-gcp-64kUbuntu

Fixed in:6.17.0-1007.7USN-8030-1

linux-image-6.17.0-1007-oracleUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-6.17.0-1007-oracle-64kUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-6.17.0-1008-azureUbuntu

Fixed in:6.17.0-1008.8USN-8029-3

linux-image-6.17.0-1008-raspiUbuntu

Fixed in:6.17.0-1008.8USN-8029-1

linux-image-6.17.0-1011-oemUbuntu

Fixed in:6.17.0-1011.11USN-8048-1

linux-image-6.17.0-14-genericUbuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-image-6.17.0-14-generic-64kUbuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-image-awsUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-aws-6.17Ubuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-aws-64kUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-aws-64k-6.17Ubuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-azureUbuntu

Fixed in:6.17.0-1008.8USN-8029-3

linux-image-azure-6.17Ubuntu

Fixed in:6.17.0-1008.8USN-8029-3

linux-image-gcpUbuntu

Fixed in:6.17.0-1007.7USN-8030-1

linux-image-gcp-6.17Ubuntu

Fixed in:6.17.0-1007.7USN-8030-1

linux-image-gcp-64kUbuntu

Fixed in:6.17.0-1007.7USN-8030-1

linux-image-gcp-64k-6.17Ubuntu

Fixed in:6.17.0-1007.7USN-8030-1

linux-image-genericUbuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-image-generic-6.17Ubuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-image-generic-64kUbuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-image-generic-64k-6.17Ubuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-image-oem-6.17Ubuntu

Fixed in:6.17.0-1011.11USN-8048-1

linux-image-oracleUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-oracle-6.17Ubuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-oracle-64kUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-oracle-64k-6.17Ubuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-image-raspiUbuntu

Fixed in:6.17.0-1008.8USN-8029-1

linux-image-raspi-6.17Ubuntu

Fixed in:6.17.0-1008.8USN-8029-1

linux-image-realtimeUbuntu

Fixed in:6.17.0-1006.7USN-8029-1

linux-image-realtime-6.17Ubuntu

Fixed in:6.17.0-1006.7USN-8029-1

linux-image-virtualUbuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-image-virtual-6.17Ubuntu

Fixed in:6.17.0-14.14USN-8029-1

linux-oem-6.17Ubuntu

Fixed in:6.17.0-1011.11USN-8048-1

linux-oracleUbuntu

Fixed in:6.17.0-1007.7USN-8029-2

linux-raspiUbuntu

Fixed in:6.17.0-1008.8USN-8029-1

linux-realtimeUbuntu

Fixed in:6.17.0-1006.7USN-8029-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.17%probability of exploitation in 30 days

6thpercentile

Low risk: more likely to be exploited than 6% of all known CVEs.

References

Other references2

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-12.