CVE-2025-38001Public exploit

Local privilege escalation via HFSC double insertion

Published Jun 6, 2025 · Updated Aug 5, 2026

Use-after-free in Linux kernel HFSC allows local users to escalate privileges or crash the host through crafted traffic-control setup. The hfsc_enqueue path tests cl_nactive for prior eligible-tree insertion, but HFSC_RSC uses init_ed without incrementing that field, allowing reentrant NETEM enqueue to insert one class twice. Exploitation requires a user and network namespace, an RSC-only HFSC class, a duplicating NETEM child, a low-rate TBF root, and locally generated packets; consequences include kernel-memory read and write access, a panic, or an infinite dequeue loop.

CVSS severity7.8
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel HFSC allows local users to escalate privileges or crash the host through crafted traffic-control setup. The hfsc_enqueue path tests cl_nactive for prior eligible-tree insertion, but HFSC_RSC uses init_ed without incrementing that field, allowing reentrant NETEM enqueue to insert one class twice. Exploitation requires a user and network namespace, an RSC-only HFSC class, a duplicating NETEM child, a low-rate TBF root, and locally generated packets; consequences include kernel-memory read and write access, a panic, or an infinite dequeue loop.

The record

CVE
CVE-2025-38001
Published
Jun 6, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 6, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record 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=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <295f7c579b07b5b7cf2dffe485f71cc2f27647cb
  2. Affected versionversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <2c928b3a0b04a431ffcd6c8b7d88a267124a3a28
  3. Affected versionversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <2f2190ce4ca972051cac6a8d7937448f8cb9673c
  4. Affected versionversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <39ed887b1dd2d6b720f87e86692ac3006cc111c8
  5. Affected versionversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <4e38eaaabfb7fffbb371a51150203e19eee5d70e
  6. Affected versionversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <6672e6c00810056acaac019fe26cdc26fee8a66c
  7. Affected versionversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <a0ec22fa20b252edbe070a9de8501eef63c17ef5
  8. Affected versionversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <ac9fe7dd8e730a103ae4481147395cc73492d786
  9. Affected versionversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <e5bee633cc276410337d54b99f77fbc1ad8801e5
  10. Affected versionversion=5.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <295f7c579b07b5b7cf2dffe485f71cc2f27647cb; version=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <2c928b3a0b04a431ffcd6c8b7d88a267124a3a28; version=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <2f2190ce4ca972051cac6a8d7937448f8cb9673c; version=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <39ed887b1dd2d6b720f87e86692ac3006cc111c8; version=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <4e38eaaabfb7fffbb371a51150203e19eee5d70e; version=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <6672e6c00810056acaac019fe26cdc26fee8a66c; version=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <a0ec22fa20b252edbe070a9de8501eef63c17ef5; version=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <ac9fe7dd8e730a103ae4481147395cc73492d786; version=37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea <e5bee633cc276410337d54b99f77fbc1ad8801e5; version=5.0

Published CVSS scores

7.8Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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 exploitPublished

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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