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      "text": "Important"
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    "category": "csaf_vex",
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    "distribution": {
      "text": "TuxCare License Agreement",
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        "url": "https://www.first.org/tlp/"
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      {
        "category": "legal_disclaimer",
        "text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Cloud Linux Inc. and provide a link to the original.",
        "title": "Terms of Use"
      }
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        "summary": "Canonical URL",
        "url": "https://security.tuxcare.com/csaf/v2/els_os/ubuntu16.04els/vex/2024/cve-2024-57896-els_os-ubuntu16_04els.json"
      }
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    "title": "Security update on CVE-2024-57896",
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      "id": "CVE-2024-57896-ELS_OS-UBUNTU16.04ELS",
      "initial_release_date": "2024-01-01T00:00:00Z",
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          "number": "1",
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          "date": "2025-06-10T09:38:30Z",
          "number": "2",
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        {
          "date": "2025-12-23T22:15:38Z",
          "number": "3",
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  "vulnerabilities": [
    {
      "cve": "CVE-2024-57896",
      "cwe": {
        "id": "CWE-416",
        "name": "Use After Free"
      },
      "notes": [
        {
          "category": "description",
          "text": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: flush delalloc workers queue before stopping cleaner kthread during unmount\n\nDuring the unmount path, at close_ctree(), we first stop the cleaner\nkthread, using kthread_stop() which frees the associated task_struct, and\nthen stop and destroy all the work queues. However after we stopped the\ncleaner we may still have a worker from the delalloc_workers queue running\ninode.c:submit_compressed_extents(), which calls btrfs_add_delayed_iput(),\nwhich in turn tries to wake up the cleaner kthread - which was already\ndestroyed before, resulting in a use-after-free on the task_struct.\n\nSyzbot reported this with the following stack traces:\n\n  BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089\n  Read of size 8 at addr ffff8880259d2818 by task kworker/u8:3/52\n\n  CPU: 1 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.13.0-rc1-syzkaller-00002-gcdd30ebb1b9f #0\n  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\n  Workqueue: btrfs-delalloc btrfs_work_helper\n  Call Trace:\n   <TASK>\n   __dump_stack lib/dump_stack.c:94 [inline]\n   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120\n   print_address_description mm/kasan/report.c:378 [inline]\n   print_report+0x169/0x550 mm/kasan/report.c:489\n   kasan_report+0x143/0x180 mm/kasan/report.c:602\n   __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089\n   lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849\n   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]\n   _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162\n   class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]\n   try_to_wake_up+0xc2/0x1470 kernel/sched/core.c:4205\n   submit_compressed_extents+0xdf/0x16e0 fs/btrfs/inode.c:1615\n   run_ordered_work fs/btrfs/async-thread.c:288 [inline]\n   btrfs_work_helper+0x96f/0xc40 fs/btrfs/async-thread.c:324\n   process_one_work kernel/workqueue.c:3229 [inline]\n   process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310\n   worker_thread+0x870/0xd30 kernel/workqueue.c:3391\n   kthread+0x2f0/0x390 kernel/kthread.c:389\n   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147\n   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n   </TASK>\n\n  Allocated by task 2:\n   kasan_save_stack mm/kasan/common.c:47 [inline]\n   kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n   unpoison_slab_object mm/kasan/common.c:319 [inline]\n   __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345\n   kasan_slab_alloc include/linux/kasan.h:250 [inline]\n   slab_post_alloc_hook mm/slub.c:4104 [inline]\n   slab_alloc_node mm/slub.c:4153 [inline]\n   kmem_cache_alloc_node_noprof+0x1d9/0x380 mm/slub.c:4205\n   alloc_task_struct_node kernel/fork.c:180 [inline]\n   dup_task_struct+0x57/0x8c0 kernel/fork.c:1113\n   copy_process+0x5d1/0x3d50 kernel/fork.c:2225\n   kernel_clone+0x223/0x870 kernel/fork.c:2807\n   kernel_thread+0x1bc/0x240 kernel/fork.c:2869\n   create_kthread kernel/kthread.c:412 [inline]\n   kthreadd+0x60d/0x810 kernel/kthread.c:767\n   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147\n   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n\n  Freed by task 24:\n   kasan_save_stack mm/kasan/common.c:47 [inline]\n   kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n   kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582\n   poison_slab_object mm/kasan/common.c:247 [inline]\n   __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264\n   kasan_slab_free include/linux/kasan.h:233 [inline]\n   slab_free_hook mm/slub.c:2338 [inline]\n   slab_free mm/slub.c:4598 [inline]\n   kmem_cache_free+0x195/0x410 mm/slub.c:4700\n   put_task_struct include/linux/sched/task.h:144 [inline]\n   delayed_put_task_struct+0x125/0x300 kernel/exit.c:227\n   rcu_do_batch kernel/rcu/tree.c:2567 [inline]\n   rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823\n   handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:554\n   run_ksoftirqd+0xca/0x130 kernel/softirq.c:943\n  \n---truncated---",
          "title": "Vulnerability description"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
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        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2024-57896"
        },
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          "category": "external",
          "summary": "https://git.kernel.org/stable/c/1ea629e7bb2fb40555e5e01a1b5095df31287017",
          "url": "https://git.kernel.org/stable/c/1ea629e7bb2fb40555e5e01a1b5095df31287017"
        },
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          "summary": "https://git.kernel.org/stable/c/35916b2f96505a18dc7242a115611b718d9de725",
          "url": "https://git.kernel.org/stable/c/35916b2f96505a18dc7242a115611b718d9de725"
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          "url": "https://git.kernel.org/stable/c/a2718ed1eb8c3611b63f8933c7e68c8821fe2808"
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          "url": "https://git.kernel.org/stable/c/f10bef73fb355e3fc85e63a50386798be68ff486"
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      "release_date": "2025-01-15T13:15:00",
      "scores": [
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          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
            "Ubuntu-16:linux-tools-4.4.0-275-tuxcare.els46-0:4.4.0-275.309.amd64",
            "Ubuntu-16:linux-libc-dev-0:4.4.0-275.309.amd64",
            "Ubuntu-16:linux-tools-4.4.0-275-tuxcare.els46-lowlatency-0:4.4.0-275.309.amd64",
            "Ubuntu-16:linux-modules-4.4.0-275-tuxcare.els46-generic-0:4.4.0-275.309.amd64",
            "Ubuntu-16:linux-modules-extra-4.4.0-275-tuxcare.els46-generic-0:4.4.0-275.309.amd64",
            "Ubuntu-16:linux-tools-host-0:4.4.0-275.309.all",
            "Ubuntu-16:linux-source-4.4.0-0:4.4.0-275.309.all",
            "Ubuntu-16:linux-headers-4.4.0-275-tuxcare.els46-0:4.4.0-275.309.all",
            "Ubuntu-16:linux-headers-4.4.0-275-tuxcare.els46-lowlatency-0:4.4.0-275.309.amd64",
            "Ubuntu-16:linux-image-unsigned-4.4.0-275-tuxcare.els46-lowlatency-0:4.4.0-275.309.amd64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "High"
        }
      ]
    }
  ]
}