CVE-2025-38177
sch_hfsc: make hfsc_qlen_notify() idempotent
Description
In the Linux kernel, the following vulnerability has been resolved: sch_hfsc: make hfsc_qlen_notify() idempotent hfsc_qlen_notify() is not idempotent either and not friendly to its callers, like fq_codel_dequeue(). Let's make it idempotent to ease qdisc_tree_reduce_backlog() callers' life: 1. update_vf() decreases cl->cl_nactive, so we can check whether it is non-zero before calling it. 2. eltree_remove() always removes RB node cl->el_node, but we can use RB_EMPTY_NODE() + RB_CLEAR_NODE() to make it safe.
INFO
Published Date :
July 4, 2025, 1:15 p.m.
Last Modified :
Aug. 28, 2025, 3:15 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the latest stable version.
- Ensure qlen_notify is called idempotently.
- Safely remove RB nodes using RB_EMPTY_NODE and RB_CLEAR_NODE.
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-2025-38177.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-38177 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-2025-38177
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).
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CVE-2025-38177 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-38177 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.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 28, 2025
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/72c61ffbeeb8c50f6d4d70c65d3283aa1bac57a7 Added Reference https://git.kernel.org/stable/c/9a5fd5c2f4d4afdd5e405083ee53e0789ce76956 Added Reference https://git.kernel.org/stable/c/a5efc95a33bd4fcb879250852828cc58c7862970 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 04, 2025
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: sch_hfsc: make hfsc_qlen_notify() idempotent hfsc_qlen_notify() is not idempotent either and not friendly to its callers, like fq_codel_dequeue(). Let's make it idempotent to ease qdisc_tree_reduce_backlog() callers' life: 1. update_vf() decreases cl->cl_nactive, so we can check whether it is non-zero before calling it. 2. eltree_remove() always removes RB node cl->el_node, but we can use RB_EMPTY_NODE() + RB_CLEAR_NODE() to make it safe. Added Reference https://git.kernel.org/stable/c/0475c85426b18eccdcb7f9fb58d8f8e9c6c58c87 Added Reference https://git.kernel.org/stable/c/51eb3b65544c9efd6a1026889ee5fb5aa62da3bb Added Reference https://git.kernel.org/stable/c/9030a91235ae4845ec71902c3e0cecfc9ed1f2df Added Reference https://git.kernel.org/stable/c/c1175c4ad01dbc9c979d099861fa90a754f72059 Added Reference https://git.kernel.org/stable/c/d06476714d2819b550e0cc39222347e2c8941c9d