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vuln-cve/data/2026/97xxx/CVE-2026-97420.json
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{
"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 <TASK>\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 </TASK>\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"
}
}
}
}