CVE-2025-40245
In the Linux kernel, the following vulnerability has been resolved:
nios2: ensure that memblock.current_limit is set when setting pfn limits
On nios2, with CONFIG_FLATMEM set, the kernel relies on memblock_get_current_limit() to determine the limits of mem_map, in particular for max_low_pfn. Unfortunately, memblock.current_limit is only default initialized to MEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading to situations where max_low_pfn can erroneously exceed the value of max_pfn and, thus, the valid range of available DRAM.
This can in turn cause kernel-level paging failures, e.g.:
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This patch fixes this by pre-calculating memblock.current_limit based on the upper limits of the available memory ranges via adjust_lowmem_bounds, a simplified version of the equivalent implementation within the arm architecture.
Detalles técnicos trazas, registros y código del informe original
[ 76.900000] Unable to handle kernel paging request at virtual address 20303000 [ 76.900000] ea = c0080890, ra = c000462c, cause = 14 [ 76.900000] Kernel panic - not syncing: Oops [ 76.900000] ---[ end Kernel panic - not syncing: Oops ]---
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 7.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.15%
- Percentil entre todas las CVEs puntuadas: 4
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation75 % - Impacto principal
T1499.004Application or System Exploitationimpact65 %
Vulnerabilidad local en kernel Linux (AV:L, PR:L) que causa panic/DoS; no hay ejecución arbitraria demostrable, pero sí negación de servicio por fallo de memoria.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/25f09699edd360b534ccae16bc276c3b52c471f3
- https://git.kernel.org/stable/c/5c3e38a367822f036227dd52bac82dc4a05157e2
- https://git.kernel.org/stable/c/8912814f14e298b83df072fecc1f7ed1b63b1b2c
- https://git.kernel.org/stable/c/90f5f715550e07cd6a51f80fc3f062d832c8c997
- https://git.kernel.org/stable/c/a20b83cf45be2057f3d073506779e52c7fa17f94
- https://git.kernel.org/stable/c/b1ec9faef7e36269ca3ec890972a78effbaeb975
JSON original (NVD)
Mostrar
{
"id": "CVE-2025-40245",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.8,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 1.8
}
]
},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae",
"lessThan": "25f09699edd360b534ccae16bc276c3b52c471f3",
"versionType": "git"
},
{
"status": "affected",
"version": "7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae",
"lessThan": "5c3e38a367822f036227dd52bac82dc4a05157e2",
"versionType": "git"
},
{
"status": "affected",
"version": "7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae",
"lessThan": "b1ec9faef7e36269ca3ec890972a78effbaeb975",
"versionType": "git"
},
{
"status": "affected",
"version": "7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae",
"lessThan": "90f5f715550e07cd6a51f80fc3f062d832c8c997",
"versionType": "git"
},
{
"status": "affected",
"version": "7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae",
"lessThan": "8912814f14e298b83df072fecc1f7ed1b63b1b2c",
"versionType": "git"
},
{
"status": "affected",
"version": "7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae",
"lessThan": "a20b83cf45be2057f3d073506779e52c7fa17f94",
"versionType": "git"
}
],
"programFiles": [
"arch/nios2/kernel/setup.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.12"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.12",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.196",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.158",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.115",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.56",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.17.6",
"versionType": "semver",
"lessThanOrEqual": "6.17.*"
},
{
"status": "unaffected",
"version": "6.18",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/nios2/kernel/setup.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2025-12-04T16:16:17.827",
"references": [
{
"url": "https://git.kernel.org/stable/c/25f09699edd360b534ccae16bc276c3b52c471f3",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/5c3e38a367822f036227dd52bac82dc4a05157e2",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/8912814f14e298b83df072fecc1f7ed1b63b1b2c",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/90f5f715550e07cd6a51f80fc3f062d832c8c997",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a20b83cf45be2057f3d073506779e52c7fa17f94",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/b1ec9faef7e36269ca3ec890972a78effbaeb975",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Deferred",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnios2: ensure that memblock.current_limit is set when setting pfn limits\n\nOn nios2, with CONFIG_FLATMEM set, the kernel relies on\nmemblock_get_current_limit() to determine the limits of mem_map, in\nparticular for max_low_pfn.\nUnfortunately, memblock.current_limit is only default initialized to\nMEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading\nto situations where max_low_pfn can erroneously exceed the value of\nmax_pfn and, thus, the valid range of available DRAM.\n\nThis can in turn cause kernel-level paging failures, e.g.:\n\n[ 76.900000] Unable to handle kernel paging request at virtual address 20303000\n[ 76.900000] ea = c0080890, ra = c000462c, cause = 14\n[ 76.900000] Kernel panic - not syncing: Oops\n[ 76.900000] ---[ end Kernel panic - not syncing: Oops ]---\n\nThis patch fixes this by pre-calculating memblock.current_limit\nbased on the upper limits of the available memory ranges via\nadjust_lowmem_bounds, a simplified version of the equivalent\nimplementation within the arm architecture."
}
],
"lastModified": "2026-07-30T06:24:21.080",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}