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NVD / CVE Program· CNA Linux

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

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 62f12cde10118253348a7540e85606869bd69432, 7207923d8453ebfb35667c1736169f2dd796772e, 873f32201df8876bdb2563e3187e79149427cab4; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1.

Low priority for now. Upgrade to Linux Linux 62f12cde10118253348a7540e85606869bd69432, 7207923d8453ebfb35667c1736169f2dd796772e, 873f32201df8876bdb2563e3187e79149427cab4; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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
Sep 5, 2025
Updated
Nov 10, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-39681

When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel
debiandebian linux

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.8affected
    • 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 and later · before 62f12cde10118253348a7540e85606869bd69432affected · git
    • 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 and later · before 873f32201df8876bdb2563e3187e79149427cab4affected · git
    • 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 and later · before fb81222c1559f89bfe3aa1010f6d112531d55353affected · git
    • 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 and later · before 7207923d8453ebfb35667c1736169f2dd796772eaffected · git
    • 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 and later · before a9e5924daa954c9f585c1ca00358afe71d6781c4affected · git
    • 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 and later · before d23264c257a70dbe021b43b3bc2ee16134cd2c69affected · git
    • 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 and later · before d8df126349dad855cdfedd6bbf315bad2e901c2faffected · git
    • before 5.8not affected · semver
    • 5.10.242 and later · up to and including 5.10.*not affected · semver
Affected versions · NVD (8)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux11.0
  • linux linux kernel5.11 and later · before 5.15.190
  • linux linux kernel5.16 and later · before 6.1.149
  • linux linux kernel6.2 and later · before 6.6.103
  • linux linux kernel5.8 and later · before 5.10.242
  • linux linux kernel6.13 and later · before 6.16.4
  • linux linux kernel6.7 and later · before 6.12.44
  • linux linux kernel6.17

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.153-16.1.153-1
Debian:13linuxbefore 6.12.48-16.12.48-1
Debian:14linuxbefore 6.16.5-16.16.5-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-39679Sep 5, 2025 · drm/nouveau/nvif: Fix potential memory leak in nvif_vmm_ctor().
    22Monitor
  • ← EarlierCVE-2025-39680Sep 5, 2025 · i2c: rtl9300: Fix out-of-bounds bug in rtl9300_i2c_smbus_xfer
    28Monitor
  • Later →CVE-2025-39682Sep 5, 2025 · tls: fix handling of zero-length records on the rx_listKEV
    70This week

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux62f12cde10118253348a7540e85606869bd69432Vendor (CNA)
Linux Linux7207923d8453ebfb35667c1736169f2dd796772eVendor (CNA)
Linux Linux873f32201df8876bdb2563e3187e79149427cab4Vendor (CNA)
Linux Linuxa9e5924daa954c9f585c1ca00358afe71d6781c4Vendor (CNA)
Linux Linuxd23264c257a70dbe021b43b3bc2ee16134cd2c69Vendor (CNA)
Linux Linuxd8df126349dad855cdfedd6bbf315bad2e901c2fVendor (CNA)
Linux Linuxfb81222c1559f89bfe3aa1010f6d112531d55353Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.05.15.200.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.153-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (11 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records