CVE-2025-39767

Soft lockup via quadratic relocation counting

Published Sep 11, 2025 · Updated Sep 11, 2025

Denial of service in Linux 5.19 through 6.17-rc2 allows local users to cause a LoongArch soft lockup during a large module load. module_frob_arch_sections() invokes count_max_entries() to find duplicate RELA entries with O(n²) comparisons, monopolizing the CPU during large loads. Reachability requires LoongArch with CONFIG_KASAN, CONFIG_PREEMPT_VOLUNTARY_BUILD, and CONFIG_PREEMPT_VOLUNTARY enabled and a sufficiently large module load.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux 5.19 through 6.17-rc2 allows local users to cause a LoongArch soft lockup during a large module load. module_frob_arch_sections() invokes count_max_entries() to find duplicate RELA entries with O(n²) comparisons, monopolizing the CPU during large loads. Reachability requires LoongArch with CONFIG_KASAN, CONFIG_PREEMPT_VOLUNTARY_BUILD, and CONFIG_PREEMPT_VOLUNTARY enabled and a sufficiently large module load.

The record

CVE
CVE-2025-39767
Published
Sep 11, 2025
Updated
Sep 11, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.19
  2. Affected versionversion=fcdfe9d22bed08409968a751e93112f742208be6 <5189c0b7c251363a4dd7678ed11b054c54f36f6f
  3. Affected versionversion=fcdfe9d22bed08409968a751e93112f742208be6 <63dbd8fb2af3a89466538599a9acb2d11ef65c06
  4. Affected versionversion=fcdfe9d22bed08409968a751e93112f742208be6 <a096b0280168d0c8b0ec1cbbfd56c8b81af8c7d8
  5. Affected versionversion=fcdfe9d22bed08409968a751e93112f742208be6 <e94cdb9fb279430cbd323a74c7ec124c85109747

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.19; version=fcdfe9d22bed08409968a751e93112f742208be6 <5189c0b7c251363a4dd7678ed11b054c54f36f6f; version=fcdfe9d22bed08409968a751e93112f742208be6 <63dbd8fb2af3a89466538599a9acb2d11ef65c06; version=fcdfe9d22bed08409968a751e93112f742208be6 <a096b0280168d0c8b0ec1cbbfd56c8b81af8c7d8; version=fcdfe9d22bed08409968a751e93112f742208be6 <e94cdb9fb279430cbd323a74c7ec124c85109747

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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