{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-97420", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-24T14:53:16.868Z", "datePublished": "2026-09-24T16:03:30.084Z", "dateUpdated": "2026-10-03T10:58:12.202Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-03T10:58:12.202Z" }, "descriptions": [ { "lang": "en", "value": "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": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/cgroup.c" ], "versions": [ { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "lessThan": "bfcee1f79aaefa90679ad47690107fb7682724ec", "status": "affected", "versionType": "git" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "lessThan": "c73e4a04eedc677fe91a736d7a5db45100adba5e", "status": "affected", "versionType": "git" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "lessThan": "36d3e9f62dc2beb9299d3bb6f589cb9e07f773fe", "status": "affected", "versionType": "git" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "lessThan": "31377675c3d75603d957c08e338a9ac27e9f6cd5", "status": "affected", "versionType": "git" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "lessThan": "76c14b10f50eb0afcc76e244562fa2d8c661e224", "status": "affected", "versionType": "git" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "lessThan": "3b2814dd842a565fcf9cc370156e1ba9eae16239", "status": "affected", "versionType": "git" }, { "version": "32927393dc1ccd60fb2bdc05b9e8e88753761469", "lessThan": "a66e3b5bacf38d6ab29fa05a9754f7a114485605", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/cgroup.c" ], "versions": [ { "version": "5.8", "status": "affected" }, { "version": "0", "lessThan": "5.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.271", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.222", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.111", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.53", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "5.10.271" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "5.15.222" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.12.111" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.18.53" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/bfcee1f79aaefa90679ad47690107fb7682724ec" }, { "url": "https://git.kernel.org/stable/c/c73e4a04eedc677fe91a736d7a5db45100adba5e" }, { "url": "https://git.kernel.org/stable/c/36d3e9f62dc2beb9299d3bb6f589cb9e07f773fe" }, { "url": "https://git.kernel.org/stable/c/31377675c3d75603d957c08e338a9ac27e9f6cd5" }, { "url": "https://git.kernel.org/stable/c/76c14b10f50eb0afcc76e244562fa2d8c661e224" }, { "url": "https://git.kernel.org/stable/c/3b2814dd842a565fcf9cc370156e1ba9eae16239" }, { "url": "https://git.kernel.org/stable/c/a66e3b5bacf38d6ab29fa05a9754f7a114485605" } ], "title": "bpf: NUL-terminate replaced sysctl value", "x_generator": { "engine": "bippy-1.2.0" } } } }