Linux Kernel up to 6.14.8 sch_hfsc hfsc_enqueue use after free

CVSS Meta Temp Score
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CTI Interest Score
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7.7$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.14.8. It has been rated as critical. Impacted is the function hfsc_enqueue of the component sch_hfsc. This manipulation causes use after free. This vulnerability is tracked as CVE-2025-38000. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.14.8. Affected by this vulnerability is the function hfsc_enqueue of the component sch_hfsc. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() When enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the child qdisc's peek() operation before incrementing sch->q.qlen and sch->qstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may trigger an immediate dequeue and potential packet drop. In such cases, qdisc_tree_reduce_backlog() is called, but the HFSC qdisc's qlen and backlog have not yet been updated, leading to inconsistent queue accounting. This can leave an empty HFSC class in the active list, causing further consequences like use-after-free. This patch fixes the bug by moving the increment of sch->q.qlen and sch->qstats.backlog before the call to the child qdisc's peek() operation. This ensures that queue length and backlog are always accurate when packet drops or dequeues are triggered during the peek.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2025-38000 since 04/16/2025. The exploitation appears to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/19/2026).

The vulnerability scanner Nessus provides a plugin with the ID 240328 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1037)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.294, 5.10.238, 5.15.185, 6.1.141, 6.6.93, 6.12.31 or 6.14.9 eliminates this vulnerability. Applying the patch 1034e3310752e8675e313f7271b348914008719a/f9f593e34d2fb67644372c8f7b033bdc622ad228/89c301e929a0db14ebd94b4d97764ce1d6981653/f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4/93c276942e75de0e5bc91576300d292e968f5a02/49b21795b8e5654a7df3d910a12e1060da4c04cf/3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335/3f981138109f63232a5fb7165938d4c945cc1b9d is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (240328), EUVD (EUVD-2025-17141) and CERT Bund (WID-SEC-2025-1270). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • Dell Avamar
  • Open Source Linux Kernel
  • Dell NetWorker
  • Dell Secure Connect Gateway

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.7

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 240328
Nessus Name: Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1037)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 5.4.294/5.10.238/5.15.185/6.1.141/6.6.93/6.12.31/6.14.9
Patch: 1034e3310752e8675e313f7271b348914008719a/f9f593e34d2fb67644372c8f7b033bdc622ad228/89c301e929a0db14ebd94b4d97764ce1d6981653/f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4/93c276942e75de0e5bc91576300d292e968f5a02/49b21795b8e5654a7df3d910a12e1060da4c04cf/3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335/3f981138109f63232a5fb7165938d4c945cc1b9d

Timelineinfo

04/16/2025 🔍
06/06/2025 +51 days 🔍
06/06/2025 +0 days 🔍
02/19/2026 +258 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-38000 (🔍)
GCVE (CVE): GCVE-0-2025-38000
GCVE (VulDB): GCVE-100-311437
EUVD: 🔍
CERT Bund: WID-SEC-2025-1270 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 06/06/2025 15:24
Updated: 02/19/2026 06:17
Changes: 06/06/2025 15:24 (59), 06/06/2025 16:22 (1), 06/24/2025 12:06 (2), 07/20/2025 19:37 (7), 08/06/2025 12:28 (1), 09/11/2025 20:38 (1), 12/16/2025 21:26 (12), 02/19/2026 06:17 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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