CVE-2025-40008
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: kmsan: fix out-of-bounds access to shadow memory Running sha224_kunit on a KMSAN-enabled kernel results in a crash in kmsan_internal_set_shadow_origin(): BUG: unable to handle page fault for address: ffffbc3840291000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary) Tainted: [N]=TEST Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100 [...] Call Trace: <TASK> __msan_memset+0xee/0x1a0 sha224_final+0x9e/0x350 test_hash_buffer_overruns+0x46f/0x5f0 ? kmsan_get_shadow_origin_ptr+0x46/0xa0 ? __pfx_test_hash_buffer_overruns+0x10/0x10 kunit_try_run_case+0x198/0xa00 This occurs when memset() is called on a buffer that is not 4-byte aligned and extends to the end of a guard page, i.e. the next page is unmapped. The bug is that the loop at the end of kmsan_internal_set_shadow_origin() accesses the wrong shadow memory bytes when the address is not 4-byte aligned. Since each 4 bytes are associated with an origin, it rounds the address and size so that it can access all the origins that contain the buffer. However, when it checks the corresponding shadow bytes for a particular origin, it incorrectly uses the original unrounded shadow address. This results in reads from shadow memory beyond the end of the buffer's shadow memory, which crashes when that memory is not mapped. To fix this, correctly align the shadow address before accessing the 4 shadow bytes corresponding to each origin.
View original CVE JSON
{
"id": "CVE-2025-40008",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2025-10-20T16:15:37.480",
"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\nkmsan: fix out-of-bounds access to shadow memory\n\nRunning sha224_kunit on a KMSAN-enabled kernel results in a crash in\nkmsan_internal_set_shadow_origin():\n\n BUG: unable to handle page fault for address: ffffbc3840291000\n #PF: supervisor read access in kernel mode\n #PF: error_code(0x0000) - not-present page\n PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0\n Oops: 0000 [#1] SMP NOPTI\n CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary)\n Tainted: [N]=TEST\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\n RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100\n [...]\n Call Trace:\n <TASK>\n __msan_memset+0xee/0x1a0\n sha224_final+0x9e/0x350\n test_hash_buffer_overruns+0x46f/0x5f0\n ? kmsan_get_shadow_origin_ptr+0x46/0xa0\n ? __pfx_test_hash_buffer_overruns+0x10/0x10\n kunit_try_run_case+0x198/0xa00\n\nThis occurs when memset() is called on a buffer that is not 4-byte aligned\nand extends to the end of a guard page, i.e. the next page is unmapped.\n\nThe bug is that the loop at the end of kmsan_internal_set_shadow_origin()\naccesses the wrong shadow memory bytes when the address is not 4-byte\naligned. Since each 4 bytes are associated with an origin, it rounds the\naddress and size so that it can access all the origins that contain the\nbuffer. However, when it checks the corresponding shadow bytes for a\nparticular origin, it incorrectly uses the original unrounded shadow\naddress. This results in reads from shadow memory beyond the end of the\nbuffer's shadow memory, which crashes when that memory is not mapped.\n\nTo fix this, correctly align the shadow address before accessing the 4\nshadow bytes corresponding to each origin."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nkmsan: corrección de acceso fuera de límites a la memoria de sombra\n\nEjecutar sha224_kunit en un kernel con KMSAN habilitado resulta en un fallo en\nkmsan_internal_set_shadow_origin():\n\n BUG: no se puede manejar el fallo de página para la dirección: ffffbc3840291000\n #PF: acceso de lectura de supervisor en modo kernel\n #PF: error_code(0x0000) - página no presente\n PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0\n Oops: 0000 [#1] SMP NOPTI\n CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary)\n Tainted: [N]=TEST\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\n RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100\n [...]\n Traza de llamadas:\n <TASK>\n __msan_memset+0xee/0x1a0\n sha224_final+0x9e/0x350\n test_hash_buffer_overruns+0x46f/0x5f0\n ? kmsan_get_shadow_origin_ptr+0x46/0xa0\n ? __pfx_test_hash_buffer_overruns+0x10/0x10\n kunit_try_run_case+0x198/0xa00\n\nEsto ocurre cuando se llama a memset() en un búfer que no está alineado a 4 bytes y se extiende hasta el final de una página de guardia, es decir, la siguiente página no está mapeada.\n\nEl error es que el bucle al final de kmsan_internal_set_shadow_origin() accede a los bytes incorrectos de la memoria de sombra cuando la dirección no está alineada a 4 bytes. Dado que cada 4 bytes están asociados con un origen, redondea la dirección y el tamaño para que pueda acceder a todos los orígenes que contienen el búfer. Sin embargo, cuando comprueba los bytes de sombra correspondientes para un origen particular, utiliza incorrectamente la dirección de sombra original sin redondear. Esto resulta en lecturas de la memoria de sombra más allá del final de la memoria de sombra del búfer, lo que provoca un fallo cuando esa memoria no está mapeada.\n\nPara solucionar esto, alinee correctamente la dirección de sombra antes de acceder a los 4 bytes de sombra correspondientes a cada origen."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"mm/kmsan/core.c",
"mm/kmsan/kmsan_test.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "9ff078f5bad8990091f1639347de5e02636e9536",
"lessThan": "e6684ed39edc35401a3341f85b1ab50a6f89a45d",
"versionType": "git",
"status": "affected"
},
{
"version": "19e85d939001946671643f4c16e1de8c633a6ce0",
"lessThan": "df1fa034c0fc229a63d01ffb20bb919b839cb576",
"versionType": "git",
"status": "affected"
},
{
"version": "2ef3cec44c60ae171b287db7fc2aa341586d65ba",
"lessThan": "f84e48707051812289b6c2684d4df2daa9d3bfbc",
"versionType": "git",
"status": "affected"
},
{
"version": "2ef3cec44c60ae171b287db7fc2aa341586d65ba",
"lessThan": "5855792c6bb9a825607845db3feaddaff0414ec3",
"versionType": "git",
"status": "affected"
},
{
"version": "2ef3cec44c60ae171b287db7fc2aa341586d65ba",
"lessThan": "85e1ff61060a765d91ee62dc5606d4d547d9d105",
"versionType": "git",
"status": "affected"
},
{
"version": "abeede7011da6c88e83ed260b909c140b8c9c250",
"versionType": "git",
"status": "affected"
},
{
"version": "6.1.94",
"lessThan": "6.1.155",
"versionType": "semver",
"status": "affected"
},
{
"version": "6.6.34",
"lessThan": "6.6.109",
"versionType": "semver",
"status": "affected"
},
{
"version": "6.9.5",
"lessThan": "6.10",
"versionType": "semver",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"mm/kmsan/core.c",
"mm/kmsan/kmsan_test.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "6.10",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.10",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.155",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.109",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.50",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.16.10",
"lessThanOrEqual": "6.16.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.17",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/5855792c6bb9a825607845db3feaddaff0414ec3",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/85e1ff61060a765d91ee62dc5606d4d547d9d105",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/df1fa034c0fc229a63d01ffb20bb919b839cb576",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/e6684ed39edc35401a3341f85b1ab50a6f89a45d",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/f84e48707051812289b6c2684d4df2daa9d3bfbc",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}