{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2021-4439", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-4439", "idYear": 2021, "status": "PUBLISHED", "publishedAt": "2024-06-20T12:07:57.944Z", "updatedAt": "2026-05-11T13:43:56.841Z", "importedAt": "2026-10-24T01:56:36.661Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "isdn: cpai: check ctr->cnr to avoid array index out of bound", "summary": "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]", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "e8b8de17e164c9f1b7777f1c6f99d05539000036" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "24219a977bfe3d658687e45615c70998acdbac5a" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "9b6b2db77bc3121fe435f1d4b56e34de443bec75" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "7d91adc0ccb060ce564103315189466eb822cc6a" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "285e9210b1fab96a11c0be3ed5cea9dd48b6ac54" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "7f221ccbee4ec662e2292d490a43ce6c314c4594" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "cc20226e218a2375d50dd9ac14fb4121b43375ff" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "status": "affected", "versionType": "git", "lessThan": "1f3e2e97c003f80c4b087092b225c8787ff91e4d" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.12" }, { "version": "4.4.290", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "4.4.*" }, { "version": "4.9.288", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "4.9.*" }, { "version": "4.14.253", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "4.14.*" }, { "version": "4.19.214", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "4.19.*" }, { "version": "5.4.156", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.4.*" }, { "version": "5.10.76", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.14.15", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.14.*" }, { "version": "5.15", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }