{
  "cveId": "CVE-2026-43402",
  "url": "https://patchblox.com/security/cve/CVE-2026-43402",
  "summary": "CVE-2026-43402 is fixed in 23 products on 1 platform, first by ALAS2023-2026-1596, released April 27, 2026. It is not reported as exploited. Patch Radar priority: Urgent.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  kthread: consolidate kthread exit paths to preve...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  kthread: consolidate kthread exit paths to prevent use-after-free  Guillaume reported crashes via corrupted RCU callback function pointers during KUnit testing. The crash was traced back to the pidfs rhashtable conversion which replaced the 24-byte rb_node with an 8-byte rhash_head in struct pid, shrinking it from 160 to 144 bytes.  struct kthread (without CONFIG_BLK_CGROUP) is also 144 bytes. With CONFIG_SLAB_MERGE_DEFAULT and SLAB_HWCACHE_ALIGN both round up to 192 bytes and share the same slab cache. struct pid.rcu.func and struct kthread.affinity_node both sit at offset 0x78.  When a kthread exits via make_task_dead() it bypasses kthread_exit() and misses the affinity_node cleanup. free_kthread_struct() frees the memory while the node is still linked into the global kthread_affinity_list. A subsequent list_del() by another kthread writes through dangling list pointers into the freed and reused memory, corrupting the pid\u0027s rcu.func pointer.  Instead of patching free_kthread_struct() to handle the missed cleanup, consolidate all kthread exit paths. Turn kthread_exit() into a macro that calls do_exit() and add kthread_do_exit() which is called from do_exit() for any task with PF_KTHREAD set. This guarantees that kthread-specific cleanup always happens regardless of the exit path - make_task_dead(), direct do_exit(), or kthread_exit().  Replace __to_kthread() with a new tsk_is_kthread() accessor in the public header. Export do_exit() since module code using the kthread_exit() macro now needs it directly.",
  "published": "2026-04-27T09:00:00Z",
  "severity": "critical",
  "cvss": 9.8,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00557,
  "epssPercentile": 0.46721,
  "priority": "Urgent",
  "priorityTier": 2,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "bpftool6.18",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.20-20.229.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "product": "bpftool6.18-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.20-20.229.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "product": "kernel-livepatch-6.18.20-20.229",
      "release": "amzn 2023",
      "fixedVersion": "1:1.0-0.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "release": "amzn 2023",
      "fixedVersion": "1:6.18.20-20.229.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "release": "amzn 2023",
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      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "product": "kernel6.18-debuginfo-common-aarch64",
      "release": "amzn 2023",
      "fixedVersion": "1:6.18.20-20.229.amzn2023",
      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "release": "amzn 2023",
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      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
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      "fix": "ALAS2023-2026-1596",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-1596",
      "released": "2026-04-27T09:00:00Z"
    },
    {
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      "fix": "ALAS2023-2026-1596",
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      "released": "2026-04-27T09:00:00Z"
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      "released": "2026-04-27T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
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      "fix": "DEBIAN-CVE-2026-43402",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-43402",
      "released": "2026-05-15T16:01:09Z"
    },
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      "released": "2026-04-27T09:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}