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        "name": "Kernel"
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  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98840.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF\n\nThe reload of 'vc' added by commit 8fb9ea65c9d1 (\"vc_screen: reload load\nof struct vc_data pointer in vcs_write() to avoid UAF\") sits after the\n'if (ret)' block, so the copy-failure break path exits the loop without\nreloading vc. If the vc was kfree()'d via vc_port_destruct during the\nunlocked copy_from_user() window, the post-loop\n'if (written \u0026\u0026 vc) vcs_scr_updated(vc)' is reached with a stale\nnon-NULL vc. The '\u0026\u0026 vc' guard from commit a287620312dc (\"vc_screen:\nfix null-ptr-deref in vcs_notifier() during concurrent vcs_write\") only\nhandles the NULL case, not this stale-non-NULL case; vcs_notifier() then\nreads param-\u003evc-\u003evc_num from freed memory:\n\n  BUG: KASAN: slab-use-after-free in vcs_notifier+0x7c/0xd0\n  Read of size 2 at addr ffff888007149190\n  Call Trace:\n   vcs_notifier+0x7c/0xd0\n   atomic_notifier_call_chain+0x70/0xa0\n   vcs_scr_updated+0x77/0xa0\n   vcs_write+0x71b/0x7e0\n  Allocated by task: vc_allocate -\u003e con_install -\u003e tty_open\n  Freed by task: kfree \u003c- vt_ioctl (VT_DISALLOCATE -\u003e vc_port_destruct)\n\nMove the reload to immediately after console_lock(), before 'if (ret)',\nso every break path below passes a fresh vc to the post-loop\nvcs_scr_updated().",
  "id": "CVE-2026-98840",
  "modified": "2026-10-19T02:30:56.406538692Z",
  "published": "2026-10-18T15:50:14.029Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1485a3dd97ab1af2605243cabe6b604546d46dd1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/226bd5603371cd9f6642cbb9e9a677f445de3530"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/233a2e190b12884d186027d0b86d43a48799b69c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9dfcadc5e003fb250dd471db90144bd5366140e9"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98840.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98840"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF"
}