CVE-2025-37890

Published May 16, 2025

Last updated 3 months ago

CVSS high 7.8

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc As described in Gerrard's report [1], we have a UAF case when an hfsc class has a netem child qdisc. The crux of the issue is that hfsc is assuming that checking for cl->qdisc->q.qlen == 0 guarantees that it hasn't inserted the class in the vttree or eltree (which is not true for the netem duplicate case). This patch checks the n_active class variable to make sure that the code won't insert the class in the vttree or eltree twice, catering for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel, debian_linux

Risk scores

CVSS 3.1

Type
Primary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-416

Social media

Hype score
Not currently trending

  1. Urgent: #SUSE releases Live Patch 41 for Linux Kernel (SLE 15 SP4/Leap 15.4). Patches 4 vulnerabilities: CVE-2025-37890, CVE-2025-38000, CVE-2025-38001 (CVSS 8.5), CVE-2025-38212 (CVSS 8.5). Read more: 👉 https://t.co/L6VAeHng7B #Security https://t.co/FyoVgvjs8m

    @Cezar_H_Linux

    13 Sept 2025

    113 Impressions

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  2. URGENT: Rocky Linux 8 #kernel-rt security update RLSA-2025:12753 is live. Patches multiple critical CVEs (CVE-2025-37890, CVE-2025-38052). Real-time kernel users must patch immediately. Read more:👉https://t.co/iciaqIvfm9 https://t.co/JWf2sZKAK3

    @Cezar_H_Linux

    9 Sept 2025

    55 Impressions

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  3. CVE-2025-37890 In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc As described in Gerr… https://t.co/QpsAraK2uA

    @CVEnew

    16 May 2025

    324 Impressions

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Configurations

Related CVEs

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References

Sources include official advisories and independent security research.