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CVE-2025-40083
net/sched: sch_qfq: Fix null-deref in agg_dequeue
Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: Fix null-deref in agg_dequeue To prevent a potential crash in agg_dequeue (net/sched/sch_qfq.c) when cl->qdisc->ops->peek(cl->qdisc) returns NULL, we check the return value before using it, similar to the existing approach in sch_hfsc.c. To avoid code duplication, the following changes are made: 1. Changed qdisc_warn_nonwc(include/net/pkt_sched.h) into a static inline function. 2. Moved qdisc_peek_len from net/sched/sch_hfsc.c to include/net/pkt_sched.h so that sch_qfq can reuse it. 3. Applied qdisc_peek_len in agg_dequeue to avoid crashing.

INFO

Published Date :

Oct. 29, 2025, 2:15 p.m.

Last Modified :

Dec. 6, 2025, 10:15 p.m.

Remotely Exploit :

No

Source :

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

The following products are affected by CVE-2025-40083 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
Solution
Apply kernel patches to fix null-dereference in agg_dequeue.
  • Update the Linux kernel.
  • Apply available patches for net/sched.
  • Rebuild and deploy the kernel.
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-2025-40083.

URL Resource
https://git.kernel.org/stable/c/1bed56f089f09b465420bf23bb32985c305cfc28
https://git.kernel.org/stable/c/3c2a8994807623c7655ece205667ae2cf74940aa
https://git.kernel.org/stable/c/6ff8e74c8f8a68ec07ef837b95425dfe900d060f
https://git.kernel.org/stable/c/6ffa9d66187188e3068b5a3895e6ae1ee34f9199
https://git.kernel.org/stable/c/71d84658a61322e5630c85c5388fc25e4a2d08b2
https://git.kernel.org/stable/c/99fc137f178797204d36ac860dd8b31e35baa2df
https://git.kernel.org/stable/c/dd831ac8221e691e9e918585b1003c7071df0379
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-40083 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-2025-40083 weaknesses.

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).

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

The following list is the news that have been mention CVE-2025-40083 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-40083 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

    Dec. 06, 2025

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/1bed56f089f09b465420bf23bb32985c305cfc28
    Added Reference https://git.kernel.org/stable/c/3c2a8994807623c7655ece205667ae2cf74940aa
    Added Reference https://git.kernel.org/stable/c/99fc137f178797204d36ac860dd8b31e35baa2df
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Dec. 03, 2025

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/71d84658a61322e5630c85c5388fc25e4a2d08b2
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Nov. 02, 2025

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/6ff8e74c8f8a68ec07ef837b95425dfe900d060f
    Added Reference https://git.kernel.org/stable/c/6ffa9d66187188e3068b5a3895e6ae1ee34f9199
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Oct. 29, 2025

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: Fix null-deref in agg_dequeue To prevent a potential crash in agg_dequeue (net/sched/sch_qfq.c) when cl->qdisc->ops->peek(cl->qdisc) returns NULL, we check the return value before using it, similar to the existing approach in sch_hfsc.c. To avoid code duplication, the following changes are made: 1. Changed qdisc_warn_nonwc(include/net/pkt_sched.h) into a static inline function. 2. Moved qdisc_peek_len from net/sched/sch_hfsc.c to include/net/pkt_sched.h so that sch_qfq can reuse it. 3. Applied qdisc_peek_len in agg_dequeue to avoid crashing.
    Added Reference https://git.kernel.org/stable/c/dd831ac8221e691e9e918585b1003c7071df0379
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.
Vulnerability Scoring Details
No CVSS metrics available for this vulnerability.