0.0
NA
CVE-2025-21971
"Linux Kernel net_sched TC_H_ROOT Class Creation Vulnerability"
Description

In the Linux kernel, the following vulnerability has been resolved: net_sched: Prevent creation of classes with TC_H_ROOT The function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination condition when traversing up the qdisc tree to update parent backlog counters. However, if a class is created with classid TC_H_ROOT, the traversal terminates prematurely at this class instead of reaching the actual root qdisc, causing parent statistics to be incorrectly maintained. In case of DRR, this could lead to a crash as reported by Mingi Cho. Prevent the creation of any Qdisc class with classid TC_H_ROOT (0xFFFFFFFF) across all qdisc types, as suggested by Jamal.

INFO

Published Date :

April 1, 2025, 4:15 p.m.

Last Modified :

April 10, 2025, 1:15 p.m.

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Remotely Exploitable :

No

Impact Score :

Exploitability Score :

Public PoC/Exploit Available at Github

CVE-2025-21971 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2025-21971 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-21971.

URL Resource
https://git.kernel.org/stable/c/003d92c91cdb5a64b25a9a74cb8543aac9a8bb48
https://git.kernel.org/stable/c/0c3057a5a04d07120b3d0ec9c79568fceb9c921e
https://git.kernel.org/stable/c/5c3ca9cb48b51bd72bf76b8b05e24f3cd53db5e7
https://git.kernel.org/stable/c/78533c4a29ac3aeddce4b481770beaaa4f3bfb67
https://git.kernel.org/stable/c/7a82fe67a9f4d7123d8e5ba8f0f0806c28695006
https://git.kernel.org/stable/c/94edfdfb9505ab608e86599d1d1e38c83816fc1c
https://git.kernel.org/stable/c/e05d9938b1b0ac40b6054cc5fa0ccbd9afd5ed4c
https://git.kernel.org/stable/c/e5ee00607bbfc97ef1526ea95b6b2458ac9e7cb7

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
oogasawa/Utility-security

None

Java

Updated: 2 weeks, 3 days ago
0 stars 0 fork 0 watcher
Born at : May 13, 2025, 2:51 a.m. This repo has been linked 137 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-21971 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2025-21971 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Apr. 10, 2025

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/003d92c91cdb5a64b25a9a74cb8543aac9a8bb48
    Added Reference https://git.kernel.org/stable/c/7a82fe67a9f4d7123d8e5ba8f0f0806c28695006
    Added Reference https://git.kernel.org/stable/c/e05d9938b1b0ac40b6054cc5fa0ccbd9afd5ed4c
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Apr. 01, 2025

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: net_sched: Prevent creation of classes with TC_H_ROOT The function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination condition when traversing up the qdisc tree to update parent backlog counters. However, if a class is created with classid TC_H_ROOT, the traversal terminates prematurely at this class instead of reaching the actual root qdisc, causing parent statistics to be incorrectly maintained. In case of DRR, this could lead to a crash as reported by Mingi Cho. Prevent the creation of any Qdisc class with classid TC_H_ROOT (0xFFFFFFFF) across all qdisc types, as suggested by Jamal.
    Added Reference https://git.kernel.org/stable/c/0c3057a5a04d07120b3d0ec9c79568fceb9c921e
    Added Reference https://git.kernel.org/stable/c/5c3ca9cb48b51bd72bf76b8b05e24f3cd53db5e7
    Added Reference https://git.kernel.org/stable/c/78533c4a29ac3aeddce4b481770beaaa4f3bfb67
    Added Reference https://git.kernel.org/stable/c/94edfdfb9505ab608e86599d1d1e38c83816fc1c
    Added Reference https://git.kernel.org/stable/c/e5ee00607bbfc97ef1526ea95b6b2458ac9e7cb7
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-21971 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-21971 weaknesses.

NONE - Vulnerability Scoring System
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Latest DB Update: Jun. 08, 2025 17:00