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LinuxCVE-2021-4439

HistoryJun 20, 2024 - 12:15 p.m.

CVE-2021-4439

2024-06-2012:15:10

CWE-129

Linux

web.nvd.nist.gov

linux kernel

cve-2021-4439

vulnerability

array index

isdn module

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

AI Score

6.2

Confidence

Low

EPSS

Percentile

5.1%

JSON

In the Linux kernel, the following vulnerability has been resolved:

isdn: cpai: check ctr->cnr 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.

__module_get(THIS_MODULE);
session-&gt;task = kthread_run(cmtp_session, session, "kcmtpd_ctr_%d",
							session-&gt;num);

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 ‘capi_ctr *[32]’
[ 46.867982][ T6479] CPU: 1 PID: 6479 Comm: kcmtpd_ctr_0 Not tainted
5.15.0-rc2+ #8
[ 46.869002][ T6479] Hardware name: QEMU Standard PC (i440FX + PIIX,
1996), BIOS 1.14.0-2 04/01/2014
[ 46.870107][ T6479] Call Trace:
[ 46.870473][ T6479] dump_stack_lvl+0x57/0x7d
[ 46.870974][ T6479] ubsan_epilogue+0x5/0x40
[ 46.871458][ T6479] __ubsan_handle_out_of_bounds.cold+0x43/0x48
[ 46.872135][ T6479] detach_capi_ctr+0x64/0xc0
[ 46.872639][ T6479] cmtp_session+0x5c8/0x5d0
[ 46.873131][ T6479] ? __init_waitqueue_head+0x60/0x60
[ 46.873712][ T6479] ? cmtp_add_msgpart+0x120/0x120
[ 46.874256][ T6479] kthread+0x147/0x170
[ 46.874709][ T6479] ? set_kthread_struct+0x40/0x40
[ 46.875248][ T6479] ret_from_fork+0x1f/0x30
[ 46.875773][ T6479]

Affected configurations

Nvd

Vulners

Node

linuxlinux_kernelRange<4.4.290

linuxlinux_kernelRange4.5–4.9.288

linuxlinux_kernelRange4.10–4.14.253

linuxlinux_kernelRange4.15–4.19.214

linuxlinux_kernelRange4.20–5.4.156

linuxlinux_kernelRange5.5–5.10.76

linuxlinux_kernelRange5.11–5.14.15

linuxlinux_kernelMatch5.15rc1

linuxlinux_kernelMatch5.15rc2

linuxlinux_kernelMatch5.15rc3

linuxlinux_kernelMatch5.15rc4

linuxlinux_kernelMatch5.15rc5

VendorProductVersionCPE
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel5.15cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
linuxlinux_kernel5.15cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
linuxlinux_kernel5.15cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
linuxlinux_kernel5.15cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
linuxlinux_kernel5.15cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:*

Vendor	Product	Version	CPE
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	5.15	cpe:2.3:o:linux:linux_kernel:5.15:rc1::::::
linux	linux_kernel	5.15	cpe:2.3:o:linux:linux_kernel:5.15:rc2::::::
linux	linux_kernel	5.15	cpe:2.3:o:linux:linux_kernel:5.15:rc3::::::
linux	linux_kernel	5.15	cpe:2.3:o:linux:linux_kernel:5.15:rc4::::::
linux	linux_kernel	5.15	cpe:2.3:o:linux:linux_kernel:5.15:rc5::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/isdn/capi/kcapi.c"
    ],
    "versions": [
      {
        "version": "1da177e4c3f4",
        "lessThan": "e8b8de17e164",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "24219a977bfe",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "9b6b2db77bc3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "7d91adc0ccb0",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "285e9210b1fa",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "7f221ccbee4e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "cc20226e218a",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "1f3e2e97c003",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/isdn/capi/kcapi.c"
    ],
    "versions": [
      {
        "version": "4.4.290",
        "lessThanOrEqual": "4.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.9.288",
        "lessThanOrEqual": "4.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.14.253",
        "lessThanOrEqual": "4.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.214",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.156",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.76",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.14.15",
        "lessThanOrEqual": "5.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]