CVE-2025-38000

Published Jun 6, 2025

Last updated 8 days ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() When enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the child qdisc's peek() operation before incrementing sch->q.qlen and sch->qstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may trigger an immediate dequeue and potential packet drop. In such cases, qdisc_tree_reduce_backlog() is called, but the HFSC qdisc's qlen and backlog have not yet been updated, leading to inconsistent queue accounting. This can leave an empty HFSC class in the active list, causing further consequences like use-after-free. This patch fixes the bug by moving the increment of sch->q.qlen and sch->qstats.backlog before the call to the child qdisc's peek() operation. This ensures that queue length and backlog are always accurate when packet drops or dequeues are triggered during the peek.
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. 🔐 Critical patch for #SUSE Linux! Update now for kernel vulnerabilities CVE-2025-38000, 38001, 38087, 38212. CVSS scores up to 8.5. Impacts SLES 15 SP6/SP7, RT, & SAP systems. Read more:👉 https://t.co/ztOM95UvUE #Security https://t.co/Rcouh7KHGZ

    @Cezar_H_Linux

    10 Sept 2025

    50 Impressions

    0 Retweets

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  3. Android vulnerability landscape shifts: CVE-2025-38004 and CVE-2025-38000 drop, new threats emerge. Details: https://t.co/tej1yYFNGt Created by AI. #Android #Cybersecurity

    @Funker_Dev

    17 Aug 2025

    32 Impressions

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  4. Latest Android CVE stats: Top threats remain CVE-2025-38004 & CVE-2025-38000. Stay informed: https://t.co/tej1yYFNGt #AndroidSecurity Created by AI. #Android #Cybersecurity

    @Funker_Dev

    2 Aug 2025

    34 Impressions

    0 Retweets

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  5. Android exploit trends show slight shifts: CVE-2025-38000 and others see variance. More details: https://t.co/tej1yYFNGt Created by AI. #Android #Cybersecurity

    @Funker_Dev

    25 Jul 2025

    7 Impressions

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  6. SIOSセキュリティブログを更新しました。 Linux Kernelの脆弱性(CVE-2025-38000〜CVE-2025-38082) #security #vulnerability #セキュリティ #脆弱性 #linux #kernel https://t.co/e3uQO9CwH3

    @omokazuki

    19 Jun 2025

    18 Impressions

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  7. CVE-2025-38000 In the Linux kernel, the following vulnerability has been resolved: sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue() When enqueuing the first pac… https://t.co/KPv4u2d9AC

    @CVEnew

    6 Jun 2025

    132 Impressions

    0 Retweets

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Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: cgroup: Avoid iteration of dying tasks with zero refcount The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()") extended the lifetime of tasks on the dying_tasks list. The iterators have provision to go through dying_tasks because of dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however, it was expected that such tasks can obtain a new reference (that is possible before cgroup_task_release()/put_task_struct_rcu_user()). The tasks after cgroup_task_release() and before cgroup_task_free() are subject to race when they may or may not have ->usage count > 0. The race window is between css_task_iter_next() invocations when css_set_lock is released and we may arrive at a new ->task_pos. The iterator should not attempt to resurrect tasks whose ->usage count dropped to zero. (When that happens, __put_task_struct_rcu_cb() is already imminent and the returned task_struct would could be used after free.) As for the fix, we cannot simply check the signal->live count of a task on the dying list because that won't distinguish regular zombies waiting to be reaped from RCU remnant tasks that are going to be free'd. Therefore add an extra check to rule out ->usage==0 tasks from any iteration. The repeat: loop in css_task_iter_advance() doesn't consider ->usage count, so add a new loop to css_task_iter_next() to skip de-used tasks on the dying_list. Rough illustration of the possible race R (reader of cgroup.procs) T (thread) L (group leader) --------------------------------- -------------------------------- -------------------------------- L exits, signal->live > 0 cgroup_task_dead(L) css_set_skip_task_iters() // skips only cset->tasks list_add_tail(&L->cg_list, &cset->dying_tasks) css_task_iter_next() take css_set_lock css_task_iter_advance() leader && signal->live != 0 => it->task_pos = &L->cg_list release css_set_lock T exits --signal->live == 0 cgroup_task_dead(T) // css_set_lock release_task(T) cgroup_task_release(T) release_task(L) // zap_leader cgroup_task_release(L) put_task_struct_rcu_user(L) ...RCU... put_task_struct(L) L->usage = 0 /* L still on dying_tasks */ ...RCU... __put_task_struct(L) css_task_iter_next() // another iteration take css_set_lock it->task_pos = &L->cg_list get_task_struct(L) => addition on 0 drop css_set_lock cgroup_task_free(L) css_set_skip_task_iters() // dying skip comes too late free_task(L) cgroup_procs_show() task_pid_vnr(L)•CVE-2026-98163