CVE-2025-37797

Published May 2, 2025

Last updated 7 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 handling This patch fixes a Use-After-Free vulnerability in the HFSC qdisc class handling. The issue occurs due to a time-of-check/time-of-use condition in hfsc_change_class() when working with certain child qdiscs like netem or codel. The vulnerability works as follows: 1. hfsc_change_class() checks if a class has packets (q.qlen != 0) 2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g., codel, netem) might drop packets and empty the queue 3. The code continues assuming the queue is still non-empty, adding the class to vttree 4. This breaks HFSC scheduler assumptions that only non-empty classes are in vttree 5. Later, when the class is destroyed, this can lead to a Use-After-Free The fix adds a second queue length check after qdisc_peek_len() to verify the queue wasn't emptied.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
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. 🚨 CRITICAL: #Ubuntu 16.04 LTS #OracleCloud kernel patches released (USN-7685-5). Multiple high-severity CVEs (inc. CVE-2025-37797, CVE-2024-56748) - risk system compromise. Read more: 👉https://t.co/37IQUckFib #Security https://t.co/6rtZp8YFok

    @Cezar_H_Linux

    13 Aug 2025

    46 Impressions

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  2. 🔒 URGENT: #openSUSE kernel patches for 3 critical CVEs (CVE-2025-37797, CVE-2025-37752, CVE-2025-21702) are live! DoS risks threaten unpatched systems—especially networks using HFSC/SFQ scheduling. 👉 https://t.co/JkPnR7DScY https://t.co/dKVwjDqDG6

    @Cezar_H_Linux

    5 Aug 2025

    38 Impressions

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  3. 🚨 Critical #LinuxKernel Patches! SUSE Live Patch 38 (SLE 15 SP4 / openSUSE Leap 15.4) fixes 4 HIGH-sev vulns: ✅ CVE-2025-37797 (HFSC UAF). ✅ CVE-2024-53125 (BPF flaw). ✅ CVE-2025-21702 (pfifo). ✅ CVE-2025-37752 (SFQ). Read more:👉 https://t.co/9xiz3h2QSu https://t.c

    @Cezar_H_Linux

    4 Aug 2025

    46 Impressions

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  4. 🚨 CVE-2025-37797 (7.8 CVSS) in Linux HFSC scheduler allows UAF attacks! SUSE Live Patch 34 out NOW for SLE 15 SP4/Leap 15.4. ⏩ Patch: zypper in -t patch SUSE-2025-2610=1 Read more: 👉 https://t.co/wHC2XZDFPy https://t.co/lp47ForYWL

    @Cezar_H_Linux

    4 Aug 2025

    37 Impressions

    0 Retweets

    1 Like

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  5. 🚨 Breaking: #SUSE Live Patch 51 for SLE 15 SP3 patches 4 high-risk kernel vulns (CVE-2024-56664, CVE-2025-37797). ✅ Affects openSUSE Leap 15.3, SAP systems. ✅ Exploits: UAF, packet drops, privilege escalation. Read more: 👉https://t.co/jNyyYnCnf7 https://t.co/nwEhA5LdV

    @Cezar_H_Linux

    4 Aug 2025

    50 Impressions

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  6. 🚨 Breaking: #Ubuntu 24.04/22.04 LTS kernel vulnerabilities (CVE-2025-38083, CVE-2025-37797) allow RCE via network subsystem. ⏱️ Low-latency environments at HIGH risk! Read more: 👉 https://t.co/eHy3mURBuh https://t.co/ahk9WPkIdp

    @Cezar_H_Linux

    1 Aug 2025

    32 Impressions

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Configurations

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References

Sources include official advisories and independent security research.