{
  "cveId": "CVE-2023-52438",
  "url": "https://patchblox.com/security/cve/CVE-2023-52438",
  "summary": "CVE-2023-52438 is fixed in linux on 1 platform, first by DEBIAN-CVE-2023-52438, released February 20, 2024. It is not reported as exploited. Patch Radar priority: High.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  binder: fix use-after-free in shinker\u0027s callback...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  binder: fix use-after-free in shinker\u0027s callback  The mmap read lock is used during the shrinker\u0027s callback, which means that using alloc-\u003Evma pointer isn\u0027t safe as it can race with munmap(). As of commit dd2283f2605e (\u0022mm: mmap: zap pages with read mmap_sem in munmap\u0022) the mmap lock is downgraded after the vma has been isolated.  I was able to reproduce this issue by manually adding some delays and triggering page reclaiming through the shrinker\u0027s debug sysfs. The following KASAN report confirms the UAF:    ==================================================================   BUG: KASAN: slab-use-after-free in zap_page_range_single\u002B0x470/0x4b8   Read of size 8 at addr ffff356ed50e50f0 by task bash/478    CPU: 1 PID: 478 Comm: bash Not tainted 6.6.0-rc5-00055-g1c8b86a3799f-dirty #70   Hardware name: linux,dummy-virt (DT)   Call trace:    zap_page_range_single\u002B0x470/0x4b8    binder_alloc_free_page\u002B0x608/0xadc    __list_lru_walk_one\u002B0x130/0x3b0    list_lru_walk_node\u002B0xc4/0x22c    binder_shrink_scan\u002B0x108/0x1dc    shrinker_debugfs_scan_write\u002B0x2b4/0x500    full_proxy_write\u002B0xd4/0x140    vfs_write\u002B0x1ac/0x758    ksys_write\u002B0xf0/0x1dc    __arm64_sys_write\u002B0x6c/0x9c    Allocated by task 492:    kmem_cache_alloc\u002B0x130/0x368    vm_area_alloc\u002B0x2c/0x190    mmap_region\u002B0x258/0x18bc    do_mmap\u002B0x694/0xa60    vm_mmap_pgoff\u002B0x170/0x29c    ksys_mmap_pgoff\u002B0x290/0x3a0    __arm64_sys_mmap\u002B0xcc/0x144    Freed by task 491:    kmem_cache_free\u002B0x17c/0x3c8    vm_area_free_rcu_cb\u002B0x74/0x98    rcu_core\u002B0xa38/0x26d4    rcu_core_si\u002B0x10/0x1c    __do_softirq\u002B0x2fc/0xd24    Last potentially related work creation:    __call_rcu_common.constprop.0\u002B0x6c/0xba0    call_rcu\u002B0x10/0x1c    vm_area_free\u002B0x18/0x24    remove_vma\u002B0xe4/0x118    do_vmi_align_munmap.isra.0\u002B0x718/0xb5c    do_vmi_munmap\u002B0xdc/0x1fc    __vm_munmap\u002B0x10c/0x278    __arm64_sys_munmap\u002B0x58/0x7c  Fix this issue by performing instead a vma_lookup() which will fail to find the vma that was isolated before the mmap lock downgrade. Note that this option has better performance than upgrading to a mmap write lock which would increase contention. Plus, mmap_write_trylock() has been recently removed anyway.",
  "published": "2024-02-20T21:15:08Z",
  "severity": "high",
  "cvss": 7.8,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00295,
  "epssPercentile": 0.22289,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.1.76-1",
      "fix": "DEBIAN-CVE-2023-52438",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-52438",
      "released": "2024-02-20T21:15:08Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.6.13-1",
      "fix": "DEBIAN-CVE-2023-52438",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-52438",
      "released": "2024-02-20T21:15:08Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "6.6.13-1",
      "fix": "DEBIAN-CVE-2023-52438",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-52438",
      "released": "2024-02-20T21:15:08Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T07:25:28Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}