CVE-2025-40174 | x86/mm: Fix SMP ordering in switch_mm_irqs_off()

In the Linux kernel, the following vulnerability has been resolved: x86/mm: Fix SMP ordering in switch_mm_irqs_off() Stephen noted that it is possible to not have an smp_mb() between the loaded_mm store and the tlb_gen load in switch_mm(), meaning the ordering against flush_tlb_mm_range() goes out the window, and it becomes possible for switch_mm() to not observe a recent tlb_gen update and fail to flush the TLBs. [ dhansen: merge conflict fixed by Ingo ]

Published: 2025-11-12 Last update: 2026-04-15 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2025-40174 is rated Low Risk (3.6/100): low exploitation likelihood (EPSS 0.02%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-40174

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-12 0.02%

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-40174

CVSS metrics for this CVE.

No CVSS data in dataset for this CVE.

Weakness enumeration for CVE-2025-40174

OS Trackers for CVE-2025-40174

vendor priority summary link
debian unimportant CVE-2025-40174 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2025-40174
redhat medium https://access.redhat.com/security/cve/CVE-2025-40174
suse medium CVE-2025-40174 severity moderate: SUSE including 26 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 269 product×package rows across 54 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Linux Enterprise High Availability Extension 15 SP7, … (54 product lines)): Known Not Affected 269. https://www.suse.com/security/cve/CVE-2025-40174/
ubuntu medium CVE-2025-40174 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1405 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1010, ignored 176, not-affected 116, released 98, needed 5. https://ubuntu.com/security/CVE-2025-40174

Affected software / configurations for CVE-2025-40174

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-40174

cvelogic Threat Intelligence