CVE-2025-39681 | x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper

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. ]

Published: 2025-09-05 Last update: 2026-06-17 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-39681 is rated Low Risk (24/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.16%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2025-39681

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 2026-06-15 0.02% 0.16% +0.14%
2 2026-01-09 0.06% 0.02% -0.04%
3 2026-01-05 — 0.06% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-39681

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2025-39681

GitHub Security Advisory for CVE-2025-39681

GHSA-xfjg-jx94-93h4 · Severity: medium — In the Linux kernel, the following vulnerability has been resolved: x86/cpu/hygon: Add missing...

OS Trackers for CVE-2025-39681

vendor priority summary link
debian not yet assigned CVE-2025-39681 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2025-39681
redhat low — https://access.redhat.com/security/cve/CVE-2025-39681
suse medium CVE-2025-39681 severity moderate: SUSE including 462 source package names (2.1.3-6.80:kernel-default-base-6.4.0-35.1.21.12, 2.1.3-7.57:kernel-default-6.4.0-35.1, …), 935 product×package rows across 190 product lines (Container suse/sl-micro/6.0/base-os-container, Container suse/sl-micro/6.0/kvm-os-container, … (190 product lines)): Fixed 619, Known Affected 231, Known Not Affected 64, First Fixed 21. https://www.suse.com/security/cve/CVE-2025-39681/
ubuntu medium CVE-2025-39681 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1414 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1017, ignored 176, released 150, not-affected 62, needed 6, needs-triage 2, pending 1. https://ubuntu.com/security/CVE-2025-39681

Affected software / configurations for CVE-2025-39681

Vendor Product Version Raw CPE
linux linux_kernel >= 5.8, < 5.10.242 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.15.190 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.149 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.6.103 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.44 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.16.4 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 6.17 cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*
linux linux_kernel 6.17 cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2025-39681

URL Tags
https://git.kernel.org/stable/c/62f12cde10118253348a7540e85606869bd69432 Patch
https://git.kernel.org/stable/c/7207923d8453ebfb35667c1736169f2dd796772e Patch
https://git.kernel.org/stable/c/873f32201df8876bdb2563e3187e79149427cab4 Patch
https://git.kernel.org/stable/c/a9e5924daa954c9f585c1ca00358afe71d6781c4 Patch
https://git.kernel.org/stable/c/d23264c257a70dbe021b43b3bc2ee16134cd2c69 Patch
https://git.kernel.org/stable/c/d8df126349dad855cdfedd6bbf315bad2e901c2f Patch
https://git.kernel.org/stable/c/fb81222c1559f89bfe3aa1010f6d112531d55353 Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Third Party Advisory
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Third Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-032379.html
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