CVE-2025-38000

Local privilege escalation via HFSC queue-accounting use-after-free

Published Jun 6, 2025 · Updated Aug 5, 2026

Use-after-free in the HFSC scheduler in Linux allows local users to elevate privileges via crafted qdisc packet traffic. hfsc_enqueue calls a child qdisc's peek operation before updating queue length and backlog, so a peek-time dequeue can underflow accounting and leave a freed class active. Triggering requires a user namespace with CAP_NET_ADMIN, a crafted HFSC hierarchy, and local traffic; the corruption enables privilege escalation or crashes or hangs the host.

CVSS severity7.8
High
EPSS probability0.23%
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 the HFSC scheduler in Linux allows local users to elevate privileges via crafted qdisc packet traffic. hfsc_enqueue calls a child qdisc's peek operation before updating queue length and backlog, so a peek-time dequeue can underflow accounting and leave a freed class active. Triggering requires a user namespace with CAP_NET_ADMIN, a crafted HFSC hierarchy, and local traffic; the corruption enables privilege escalation or crashes or hangs the host.

The record

CVE
CVE-2025-38000
Published
Jun 6, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
Unavailable

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=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <1034e3310752e8675e313f7271b348914008719a
  2. Affected versionversion=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335
  3. Affected versionversion=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <3f981138109f63232a5fb7165938d4c945cc1b9d
  4. Affected versionversion=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <49b21795b8e5654a7df3d910a12e1060da4c04cf
  5. Affected versionversion=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <89c301e929a0db14ebd94b4d97764ce1d6981653
  6. Affected versionversion=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <93c276942e75de0e5bc91576300d292e968f5a02
  7. Affected versionversion=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4
  8. Affected versionversion=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <f9f593e34d2fb67644372c8f7b033bdc622ad228
  9. Affected versionversion=4.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <1034e3310752e8675e313f7271b348914008719a; version=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335; version=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <3f981138109f63232a5fb7165938d4c945cc1b9d; version=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <49b21795b8e5654a7df3d910a12e1060da4c04cf; version=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <89c301e929a0db14ebd94b4d97764ce1d6981653; version=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <93c276942e75de0e5bc91576300d292e968f5a02; version=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4; version=12d0ad3be9c3854e52ec74bb83bb6f43612827c7 <f9f593e34d2fb67644372c8f7b033bdc622ad228; version=4.8

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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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