{
  "cveId": "CVE-2021-4439",
  "url": "https://patchblox.com/security/cve/CVE-2021-4439",
  "summary": "CVE-2021-4439 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-4439, released June 20, 2024. It is not reported as exploited. Patch Radar priority: High.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  isdn: cpai: check ctr-\u003Ecnr to avoid array index...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  isdn: cpai: check ctr-\u003Ecnr to avoid array index out of bound  The cmtp_add_connection() would add a cmtp session to a controller and run a kernel thread to process cmtp.  \t__module_get(THIS_MODULE); \tsession-\u003Etask = kthread_run(cmtp_session, session, \u0022kcmtpd_ctr_%d\u0022, \t\t\t\t\t\t\t\tsession-\u003Enum);  During this process, the kernel thread would call detach_capi_ctr() to detach a register controller. if the controller was not attached yet, detach_capi_ctr() would trigger an array-index-out-bounds bug.  [   46.866069][ T6479] UBSAN: array-index-out-of-bounds in drivers/isdn/capi/kcapi.c:483:21 [   46.867196][ T6479] index -1 is out of range for type \u0027capi_ctr *[32]\u0027 [   46.867982][ T6479] CPU: 1 PID: 6479 Comm: kcmtpd_ctr_0 Not tainted 5.15.0-rc2\u002B #8 [   46.869002][ T6479] Hardware name: QEMU Standard PC (i440FX \u002B PIIX, 1996), BIOS 1.14.0-2 04/01/2014 [   46.870107][ T6479] Call Trace: [   46.870473][ T6479]  dump_stack_lvl\u002B0x57/0x7d [   46.870974][ T6479]  ubsan_epilogue\u002B0x5/0x40 [   46.871458][ T6479]  __ubsan_handle_out_of_bounds.cold\u002B0x43/0x48 [   46.872135][ T6479]  detach_capi_ctr\u002B0x64/0xc0 [   46.872639][ T6479]  cmtp_session\u002B0x5c8/0x5d0 [   46.873131][ T6479]  ? __init_waitqueue_head\u002B0x60/0x60 [   46.873712][ T6479]  ? cmtp_add_msgpart\u002B0x120/0x120 [   46.874256][ T6479]  kthread\u002B0x147/0x170 [   46.874709][ T6479]  ? set_kthread_struct\u002B0x40/0x40 [   46.875248][ T6479]  ret_from_fork\u002B0x1f/0x30 [   46.875773][ T6479]",
  "published": "2024-06-20T12:15:10Z",
  "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": 0.00235,
  "epssPercentile": 0.14526,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.14.16-1",
      "fix": "DEBIAN-CVE-2021-4439",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-4439",
      "released": "2024-06-20T12:15:10Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.14.16-1",
      "fix": "DEBIAN-CVE-2021-4439",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-4439",
      "released": "2024-06-20T12:15:10Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.14.16-1",
      "fix": "DEBIAN-CVE-2021-4439",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-4439",
      "released": "2024-06-20T12:15:10Z"
    }
  ],
  "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"
  }
}