How severe is CVE-2025-39681?

CVE-2025-39681 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-39681 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-39681?

CVE-2025-39681 primarily affects Linux Linux Kernel. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-39681?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-39681 have an EU (EUVD) identifier?

Yes. CVE-2025-39681 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-31543.

When was CVE-2025-39681 published?

CVE-2025-39681 was published on 2025-09-05 and last updated on 2026-06-17.

CVE-2025-39681

CVE-2025-39681 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-31543
Affected product: Linux Linux Kernel
Published: 2025-09-05
Last modified: 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper Since 923f3a2b48bd ("x86/resctrl: Query LLC monitoring properties once during boot") resctrl_cpu_detect() has been moved from common CPU initialization code to the vendor-specific BSP init helper, while Hygon didn't put that call in their code. This triggers a division by zero fault during early booting stage on our machines with X86_FEATURE_CQM* supported, where get_rdt_mon_resources() tries to calculate mon_l3_config with uninitialized boot_cpu_data.x86_cache_occ_scale. Add the missing resctrl_cpu_detect() in the Hygon BSP init helper. [ bp: Massage commit message. ]

Frequently asked questions

What is CVE-2025-39681?: In the Linux kernel, the following vulnerability has been resolved: x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper Since 923f3a2b48bd ("x86/resctrl: Query LLC monitoring properties once during boot") resctrl_cpu_detect() has been moved from common CPU initialization code to the vendor-specific BSP init helper, while Hygon didn't put that call in their code. This triggers a division by zero fault during early booting stage on our machines with X86_FEATURE_CQM* supported, where get_rdt_mon_resources() tries to calculate mon_l3_config with uninitialized boot_cpu_data.x86_cache_occ_scale. Add the missing resctrl_cpu_detect() in the Hygon BSP init helper. [ bp: Massage commit message. ]
How severe is CVE-2025-39681?: CVE-2025-39681 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-39681 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-39681?: CVE-2025-39681 primarily affects Linux Linux Kernel. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-39681?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-39681 have an EU (EUVD) identifier?: Yes. CVE-2025-39681 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-31543.
When was CVE-2025-39681 published?: CVE-2025-39681 was published on 2025-09-05 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

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