{ "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-2026-97420", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-97420", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-09-24T16:03:30.084Z", "updatedAt": "2026-10-03T10:58:12.202Z", "importedAt": "2026-10-24T01:58:41.756Z", "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": "bpf: NUL-terminate replaced sysctl value", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: NUL-terminate replaced sysctl value\n\nWhen writing to sysctls, proc_sys_call_handler() guarantees that the\nbuffer passed to proc handlers is NUL-terminated. If\nbpf_sysctl_set_new_value() replaces the pending sysctl value, it can\nhand a replacement buffer directly to proc handlers. However, the\nhelper currently copies only buf_len bytes into that buffer without\nappending a NUL terminator, leaving downstream parsers vulnerable to\nout-of-bounds access.\n\nFix this by appending a '\\0' after the replaced value to restore the\nexpected sysctl semantics. Since the helper already rejects buf_len\ngreater than PAGE_SIZE - 1, there is always room for the extra byte.\n\nReproduced in a QEMU x86_64 guest booted with KASAN while exercising\nthe sysctl replacement path with a cgroup/sysctl BPF program. The\nreproducer targets `/proc/sys/net/core/flow_limit_cpu_bitmap`, fills\nthe original user write buffer with non-zero bytes, and overrides the\nsysctl value so the replacement buffer lacks a terminating NUL. Under\nthat setup, the pre-fix kernel reported:\n\n BUG: KASAN: slab-out-of-bounds in strnchrnul+0x72/0x90\n Read of size 1 at addr ffff88800de57000 by task repro_patch3/66\n CPU: 0 UID: 0 PID: 66 Comm: repro_patch3 Not tainted 7.1.0-rc3-00269-g8370ca1f87cc #6 PREEMPT(lazy)\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\n Call Trace:\n \n dump_stack_lvl+0x68/0xa0\n print_report+0xcb/0x5e0\n ? __virt_addr_valid+0x21d/0x3f0\n ? strnchrnul+0x72/0x90\n ? strnchrnul+0x72/0x90\n kasan_report+0xca/0x100\n ? strnchrnul+0x72/0x90\n strnchrnul+0x72/0x90\n bitmap_parse+0x37/0x2e0\n flow_limit_cpu_sysctl+0xc6/0x840\n ? __pfx_flow_limit_cpu_sysctl+0x10/0x10\n ? __kvmalloc_node_noprof+0x5ba/0x870\n proc_sys_call_handler+0x31d/0x480\n ? __pfx_proc_sys_call_handler+0x10/0x10\n ? selinux_file_permission+0x39f/0x500\n ? lock_is_held_type+0x9e/0x120\n vfs_write+0x98e/0x1000\n ...\n \n The buggy address is located 0 bytes to the right of\n allocated 4096-byte region [ffff88800de56000, ffff88800de57000)\nWith this fix applied, rerunning the same sysctl-targeted path yields\nno corresponding KASAN reports.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "status": "affected", "versionType": "git", "lessThan": "bfcee1f79aaefa90679ad47690107fb7682724ec" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "status": "affected", "versionType": "git", "lessThan": "c73e4a04eedc677fe91a736d7a5db45100adba5e" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "status": "affected", "versionType": "git", "lessThan": "36d3e9f62dc2beb9299d3bb6f589cb9e07f773fe" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "status": "affected", "versionType": "git", "lessThan": "31377675c3d75603d957c08e338a9ac27e9f6cd5" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "status": "affected", "versionType": "git", "lessThan": "76c14b10f50eb0afcc76e244562fa2d8c661e224" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "status": "affected", "versionType": "git", "lessThan": "3b2814dd842a565fcf9cc370156e1ba9eae16239" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "status": "affected", "versionType": "git", "lessThan": "a66e3b5bacf38d6ab29fa05a9754f7a114485605" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.8", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.8" }, { "version": "5.10.271", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.222", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.189", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.158", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.111", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.53", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }