CVE-2025-38001

MEDIUM

Linux Kernel 5.0.1-6.15.0 Use-After-Free and Infinite Loop via HFSC and NETEM

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 5 public exploits for CVE-2025-38001. PoCs published by 0xdevil, khoatran107, aexdyhaxor.

AI-analyzed exploit summary This is a Linux kernel exploit for CVE-2025-38001, targeting a use-after-free vulnerability in the HFSC (Hierarchical Fair Service Curve) qdisc implementation. The exploit leverages RBTree manipulations to achieve arbitrary code execution, with support for multiple kernel versions including LTS 6.6 and COS 6.1.

Description

In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Address reentrant enqueue adding class to eltree twice Savino says: "We are writing to report that this recent patch (141d34391abbb315d68556b7c67ad97885407547) [1] can be bypassed, and a UAF can still occur when HFSC is utilized with NETEM. The patch only checks the cl->cl_nactive field to determine whether it is the first insertion or not [2], but this field is only incremented by init_vf [3]. By using HFSC_RSC (which uses init_ed) [4], it is possible to bypass the check and insert the class twice in the eltree. Under normal conditions, this would lead to an infinite loop in hfsc_dequeue for the reasons we already explained in this report [5]. However, if TBF is added as root qdisc and it is configured with a very low rate, it can be utilized to prevent packets from being dequeued. This behavior can be exploited to perform subsequent insertions in the HFSC eltree and cause a UAF." To fix both the UAF and the infinite loop, with netem as an hfsc child, check explicitly in hfsc_enqueue whether the class is already in the eltree whenever the HFSC_RSC flag is set. [1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=141d34391abbb315d68556b7c67ad97885407547 [2] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1572 [3] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L677 [4] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1574 [5] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/T/#u

Exploits (5)

nomisec WORKING POC 93 stars
by 0xdevil · poc
https://github.com/0xdevil/CVE-2025-38001

This is a Linux kernel exploit for CVE-2025-38001, targeting a use-after-free vulnerability in the HFSC (Hierarchical Fair Service Curve) qdisc implementation. The exploit leverages RBTree manipulations to achieve arbitrary code execution, with support for multiple kernel versions including LTS 6.6 and COS 6.1.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Reliable
Target: Linux Kernel (Debian 12, LTS 6.6.90, COS 109, COS 105)
No auth needed
Prerequisites: Linux kernel with vulnerable HFSC qdisc implementation · Unprivileged user access
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 1 stars
by khoatran107 · poc
https://github.com/khoatran107/cve-2025-38001

This repository contains a proof-of-concept exploit for CVE-2025-38001, targeting a vulnerability in the Linux kernel's HFSC (Hierarchical Fair Service Curve) scheduler. The exploit appears to focus on a memory corruption or logic flaw in the `hfsc_class` structure, particularly around the `cl_nactive` field.

Classification
Working Poc 80%
Attack Type
Lpe
Complexity
Complex
Reliability
Theoretical
Target: Linux Kernel (likely versions up to 6.6.90)
No auth needed
Prerequisites: Access to a vulnerable Linux system with the HFSC scheduler in use
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by aexdyhaxor · poc
https://github.com/aexdyhaxor/CVE-2025-38001

This repository contains a functional exploit for CVE-2025-38001, targeting a use-after-free vulnerability in the Linux Kernel's HFSC (Hierarchical Fair Service Curve) RBTree implementation. The exploit demonstrates privilege escalation by manipulating kernel memory structures to achieve root access.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Reliable
Target: Linux Kernel (versions 5.15, 6.1, 6.6)
No auth needed
Prerequisites: Linux kernel with HFSC module loaded · unprivileged user access
devstral-2 · analyzed Mar 12, 2026 Full analysis →
nomisec WORKING POC
by boeseejykbtanke348 · poc
https://github.com/boeseejykbtanke348/CVE-2025-38001

This repository provides a working proof-of-concept exploit for CVE-2025-41744, which involves the use of a default cryptographic key in Sprecher Automation SPRECON-E-C devices. The exploit includes tools to intercept and decrypt network traffic using the hardcoded AES-256 key.

Classification
Working Poc 90%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Sprecher Automation SPRECON-E-C series devices
No auth needed
Prerequisites: Network access to target device · Wireshark for traffic capture · Python 3.10+ for auxiliary scripts
devstral-2 · analyzed Feb 16, 2026 Full analysis →

Scores

CVSS v3 5.5
EPSS 0.0003
EPSS Percentile 8.4%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-835
Status published
Products (32)
debian/debian_linux 11.0
debian/debian_linux 12.0
linux/Kernel 5.0.0 - 5.4.294linux
linux/Kernel 5.11.0 - 5.15.185linux
linux/Kernel 5.16.0 - 6.1.141linux
linux/Kernel 5.5.0 - 5.10.238linux
linux/Kernel 6.13.0 - 6.14.10linux
linux/Kernel 6.15.0 - 6.15.1linux
linux/Kernel 6.2.0 - 6.6.93linux
linux/Kernel 6.7.0 - 6.12.32linux
... and 22 more
Published Jun 06, 2025
Tracked Since Feb 18, 2026