CVE-2025-37932 | sch_htb: make htb_qlen_notify() idempotent

In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_qlen_notify() idempotent htb_qlen_notify() always deactivates the HTB class and in fact could trigger a warning if it is already deactivated. Therefore, it is not idempotent and not friendly to its callers, like fq_codel_dequeue(). Let's make it idempotent to ease qdisc_tree_reduce_backlog() callers' life.

Published: 2025-05-20 Last update: 2025-12-19 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-37932 is rated Low Risk (31.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.09%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-37932

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-16 0.03% 0.09% +0.06%
2 2025-12-20 0.06% 0.03% -0.03%
3 2025-10-28 — 0.06% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-37932

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2025-37932

OS Trackers for CVE-2025-37932

vendor priority summary link
debian not yet assigned CVE-2025-37932 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2025-37932
redhat low — https://access.redhat.com/security/cve/CVE-2025-37932
suse medium — https://www.suse.com/security/cve/CVE-2025-37932/
ubuntu medium CVE-2025-37932 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, released 226, ignored 148, not-affected 28, needed 2, needs-triage 2. https://ubuntu.com/security/CVE-2025-37932

Affected software / configurations for CVE-2025-37932

Vendor Product Version Raw CPE
linux linux_kernel < 5.4.294 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.5, < 5.10.241 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.15.190 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.138 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.6.90 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.28 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.14.6 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 6.15 cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2025-37932

URL Tags
https://git.kernel.org/stable/c/0a188c0e197383683fd093ab1ea6ce9a5869a6ea Patch
https://git.kernel.org/stable/c/32ae12ce6a9f6bace186ca7335220ff59b6cc3cd Patch
https://git.kernel.org/stable/c/5ba8b837b522d7051ef81bacf3d95383ff8edce5 Patch
https://git.kernel.org/stable/c/73cf6af13153d62f9b76eff422eea79dbc70f15e Patch
https://git.kernel.org/stable/c/967955c9e57f8eebfccc298037d4aaf3d42bc1c9 Patch
https://git.kernel.org/stable/c/a61f1b5921761fbaf166231418bc1db301e5bf59 Patch
https://git.kernel.org/stable/c/bbbf5e0f87078b715e7a665d662a2c0e77f044ae Patch
https://git.kernel.org/stable/c/e6b45f4de763b00dc1c55e685e2dd1aaf525d3c1 Patch
https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html Third Party Advisory
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Third Party Advisory
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