CVE-2025-38177: debian linux — Fix

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-459 CWE-459

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 5.4.297
linux	linux_kernel	5.5 — 5.10.241
linux	linux_kernel	5.11 — 5.15.190
linux	linux_kernel	5.16 — 6.1.138
linux	linux_kernel	6.2 — 6.6.90
linux	linux_kernel	6.7 — 6.12.28
linux	linux_kernel	6.13 — 6.14.6
linux	linux_kernel	All
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/0475c85426b18eccdcb7f9fb58d8f8e9c6c58c87 https://git.kernel.org/stable/c/51eb3b65544c9efd6a1026889ee5fb5aa62da3bb https://git.kernel.org/stable/c/72c61ffbeeb8c50f6d4d70c65d3283aa1bac57a7 https://git.kernel.org/stable/c/9030a91235ae4845ec71902c3e0cecfc9ed1f2df https://git.kernel.org/stable/c/9a5fd5c2f4d4afdd5e405083ee53e0789ce76956 https://git.kernel.org/stable/c/a5efc95a33bd4fcb879250852828cc58c7862970 https://git.kernel.org/stable/c/c1175c4ad01dbc9c979d099861fa90a754f72059 https://git.kernel.org/stable/c/d06476714d2819b550e0cc39222347e2c8941c9d

Other References

https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html

Frequently Asked Questions

What is CVE-2025-38177? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-38177? +

CVE-2025-38177 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-38177? +

CVE-2025-38177 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38177? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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