CVE-2025-40168: smc: Use __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match().

mediumCVSS 6.3CVE-2025-40168

CSIRTS triage

vendor: Linux product: Linux Kernel Memory corruption

What: SMC (Shared Memory Communications) protocol uses unsafe socket functions without proper RCU synchronization in smc_clc_prfx_match().
Who is affected: Linux systems using SMC protocol for network communication.
Urgency: Medium severity (CVSS 6.3) memory safety issue; requires network access and SMC protocol use.
Action: Apply kernel patch using __sk_dst_get() and dst_dev_rcu() for proper RCU locking in SMC prefix matching.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 6.3
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-40168

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2025-401680.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2025-40168	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[UPDATE] [high] Linux Kernel: Multiple vulnerabilitiescert-bund

Recent advisories for smc

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-74719: In the Linux kernel, the following vulnerability has been resolved: net/smc: fix qentry overwr…nvd · 2026-08-22
highCVE-2026-74692: In the Linux kernel, the following vulnerability has been resolved: net/smc: fix TOCTOU race b…nvd · 2026-08-22
highCVE-2026-74631: In the Linux kernel, the following vulnerability has been resolved: net: smc: fix splice entry…nvd · 2026-08-22
criticalCVE-2026-74493: In the Linux kernel, the following vulnerability has been resolved: net/smc: fix socket use-af…nvd · 2026-08-15
mediumCVE-2026-74692: net/smc: fix TOCTOU race between smc_listen_out() and listener closemsrc · 2026-08-11
mediumCVE-2026-74631: net: smc: fix splice entry lifetime imbalance in smc_rx_splicemsrc · 2026-08-11