CVE-2025-40169
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject negative offsets for ALU ops When verifying BPF programs, the check_alu_op() function validates instructions with ALU operations. The 'offset' field in these instructions is a signed 16-bit integer. The existing check 'insn->off > 1' was intended to ensure the offset is either 0, or 1 for BPF_MOD/BPF_DIV. However, because 'insn->off' is signed, this check incorrectly accepts all negative values (e.g., -1). This commit tightens the validation by changing the condition to '(insn->off != 0 && insn->off != 1)'. This ensures that any value other than the explicitly permitted 0 and 1 is rejected, hardening the verifier against malformed BPF programs.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Deferred
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-11-12 11:15:47.270000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON
{
"id": "CVE-2025-40169",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2025-11-12T11:15:47.270",
"lastModified": "2026-10-19T21:10:00.160",
"vulnStatus": "Deferred",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject negative offsets for ALU ops\n\nWhen verifying BPF programs, the check_alu_op() function validates\ninstructions with ALU operations. The 'offset' field in these\ninstructions is a signed 16-bit integer.\n\nThe existing check 'insn->off > 1' was intended to ensure the offset is\neither 0, or 1 for BPF_MOD/BPF_DIV. However, because 'insn->off' is\nsigned, this check incorrectly accepts all negative values (e.g., -1).\n\nThis commit tightens the validation by changing the condition to\n'(insn->off != 0 && insn->off != 1)'. This ensures that any value\nother than the explicitly permitted 0 and 1 is rejected, hardening the\nverifier against malformed BPF programs."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nbpf: Rechazar offsets negativos para operaciones ALU\n\nAl verificar programas BPF, la función check_alu_op() valida instrucciones con operaciones ALU. El campo 'offset' en estas instrucciones es un entero con signo de 16 bits.\n\nLa comprobación existente 'insn->off > 1' tenía la intención de asegurar que el offset sea 0 o 1 para BPF_MOD/BPF_DIV. Sin embargo, debido a que 'insn->off' tiene signo, esta comprobación acepta incorrectamente todos los valores negativos (p. ej., -1).\n\nEste commit endurece la validación al cambiar la condición a '(insn->off != 0 && insn->off != 1)'. Esto asegura que cualquier valor distinto de los 0 y 1 explícitamente permitidos sea rechazado, endureciendo el verificador contra programas BPF malformados."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"kernel/bpf/verifier.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "3bce44b344040e5eef3d64d38b157c15304c0aab",
"versionType": "git",
"status": "affected"
},
{
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "5017c302ca4b2a45149ad64e058fa2d5623c068f",
"versionType": "git",
"status": "affected"
},
{
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "21167bf70dbe400563e189ac632258d35eda38b5",
"versionType": "git",
"status": "affected"
},
{
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "55c0ced59fe17dee34e9dfd5f7be63cbab207758",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"kernel/bpf/verifier.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "6.6",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.6",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.112",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.53",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.17.3",
"lessThanOrEqual": "6.17.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-15T21:57:30.151635Z",
"id": "CVE-2025-40169",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/21167bf70dbe400563e189ac632258d35eda38b5",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/3bce44b344040e5eef3d64d38b157c15304c0aab",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/5017c302ca4b2a45149ad64e058fa2d5623c068f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/55c0ced59fe17dee34e9dfd5f7be63cbab207758",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}