{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2021-4439",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nisdn: cpai: check ctr->cnr to avoid array index out of bound\n\nThe cmtp_add_connection() would add a cmtp session to a controller\nand run a kernel thread to process cmtp.\n\n\t__module_get(THIS_MODULE);\n\tsession->task = kthread_run(cmtp_session, session, \"kcmtpd_ctr_%d\",\n\t\t\t\t\t\t\t\tsession->num);\n\nDuring this process, the kernel thread would call detach_capi_ctr()\nto detach a register controller. if the controller\nwas not attached yet, detach_capi_ctr() would\ntrigger an array-index-out-bounds bug.\n\n[   46.866069][ T6479] UBSAN: array-index-out-of-bounds in\ndrivers/isdn/capi/kcapi.c:483:21\n[   46.867196][ T6479] index -1 is out of range for type 'capi_ctr *[32]'\n[   46.867982][ T6479] CPU: 1 PID: 6479 Comm: kcmtpd_ctr_0 Not tainted\n5.15.0-rc2+ #8\n[   46.869002][ T6479] Hardware name: QEMU Standard PC (i440FX + PIIX,\n1996), BIOS 1.14.0-2 04/01/2014\n[   46.870107][ T6479] Call Trace:\n[   46.870473][ T6479]  dump_stack_lvl+0x57/0x7d\n[   46.870974][ T6479]  ubsan_epilogue+0x5/0x40\n[   46.871458][ T6479]  __ubsan_handle_out_of_bounds.cold+0x43/0x48\n[   46.872135][ T6479]  detach_capi_ctr+0x64/0xc0\n[   46.872639][ T6479]  cmtp_session+0x5c8/0x5d0\n[   46.873131][ T6479]  ? __init_waitqueue_head+0x60/0x60\n[   46.873712][ T6479]  ? cmtp_add_msgpart+0x120/0x120\n[   46.874256][ T6479]  kthread+0x147/0x170\n[   46.874709][ T6479]  ? set_kthread_struct+0x40/0x40\n[   46.875248][ T6479]  ret_from_fork+0x1f/0x30\n[   46.875773][ T6479]"
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Linux",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Linux",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "<",
                                            "version_name": "1da177e4c3f4",
                                            "version_value": "e8b8de17e164"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "4.4.290",
                                                        "lessThanOrEqual": "4.4.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "4.9.288",
                                                        "lessThanOrEqual": "4.9.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "4.14.253",
                                                        "lessThanOrEqual": "4.14.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "4.19.214",
                                                        "lessThanOrEqual": "4.19.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "5.4.156",
                                                        "lessThanOrEqual": "5.4.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "5.10.76",
                                                        "lessThanOrEqual": "5.10.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "5.14.15",
                                                        "lessThanOrEqual": "5.14.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "5.15",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/e8b8de17e164c9f1b7777f1c6f99d05539000036",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/e8b8de17e164c9f1b7777f1c6f99d05539000036"
            },
            {
                "url": "https://git.kernel.org/stable/c/24219a977bfe3d658687e45615c70998acdbac5a",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/24219a977bfe3d658687e45615c70998acdbac5a"
            },
            {
                "url": "https://git.kernel.org/stable/c/9b6b2db77bc3121fe435f1d4b56e34de443bec75",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/9b6b2db77bc3121fe435f1d4b56e34de443bec75"
            },
            {
                "url": "https://git.kernel.org/stable/c/7d91adc0ccb060ce564103315189466eb822cc6a",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/7d91adc0ccb060ce564103315189466eb822cc6a"
            },
            {
                "url": "https://git.kernel.org/stable/c/285e9210b1fab96a11c0be3ed5cea9dd48b6ac54",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/285e9210b1fab96a11c0be3ed5cea9dd48b6ac54"
            },
            {
                "url": "https://git.kernel.org/stable/c/7f221ccbee4ec662e2292d490a43ce6c314c4594",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/7f221ccbee4ec662e2292d490a43ce6c314c4594"
            },
            {
                "url": "https://git.kernel.org/stable/c/cc20226e218a2375d50dd9ac14fb4121b43375ff",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/cc20226e218a2375d50dd9ac14fb4121b43375ff"
            },
            {
                "url": "https://git.kernel.org/stable/c/1f3e2e97c003f80c4b087092b225c8787ff91e4d",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/1f3e2e97c003f80c4b087092b225c8787ff91e4d"
            }
        ]
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    "generator": {
        "engine": "bippy-c8e10e5f6187"
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}