CVE-2026-89777
Estado: RecibidaAlta (8.8)—
In the Linux kernel, the following vulnerability has been resolved:
vfio/pci: clear vdev->msi_perm after freeing it on init failure
vfio_msi_cap_len() lazily allocates the per-device MSI permission table:
When init_pci_cap_msi_perm() -> alloc_perm_bits() fails with -ENOMEM, the error path frees vdev->msi_perm but leaves the freed pointer stored in it. vdev->msi_perm is not re-zeroed later because struct vfio_pci_core_device is per-device and persists across open/close cycles, and the vfio_config_init() error path returns without calling vfio_config_free(). So the dangling pointer outlives the failed open.
Leer descripción completaMostrar menos
That leads to two use-after-frees on the same device:
Fix it by NULLing vdev->msi_perm after the kfree(), matching the NULL-after-free discipline already used in free_perm_bits() and vfio_config_free().
Followed on device close by a double free of the same object:
Detalles técnicos trazas, registros y código del informe original
vdev->msi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT);
if (!vdev->msi_perm)
return -ENOMEM;
ret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags);
if (ret) {
kfree(vdev->msi_perm);
return ret; /* vdev->msi_perm left dangling */
}
1. Reuse. The next vfio_config_init() sees the stale pointer at
"if (vdev->msi_perm) return len;" and reuses the freed object. MSI
config accesses in vfio_pci_config_rw_single() then dereference and
call the freed perm->readfn / perm->writefn function pointers.
2. Double free. A later vfio_config_free() runs free_perm_bits() and
kfree() on the already-freed object.
BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)
Read of size 8 at addr ffff88800fcc88d0 by task exploit/143
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)
vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986)
vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599)
vfs_read (fs/read_write.c:572)
__x64_sys_pread64 (fs/read_write.c:764)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
...
Oops: general protection fault, probably for non-canonical address
0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:kfree (mm/slub.c:6711)
Call Trace:
vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861)
vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685)
vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777)
vfio_df_close (drivers/vfio/vfio_main.c:602)
vfio_device_fops_release (drivers/vfio/vfio_main.c:648)
__fput (fs/file_table.c:512)
__x64_sys_close (fs/open.c:1496)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
...
Kernel panic - not syncing: Fatal exceptionCVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Puntuación base: 8.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.16%
- Percentil entre todas las CVEs puntuadas: 5
- 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 escalation85 % - Impacto principal
T1059Command and Scripting Interpreterexecution80 % - Impacto secundario
T1499.004Application or System Exploitationimpact75 %
AV:L/PR:L permite escalada local; use-after-free con dereference de function pointers habilita ejecución de código arbitrario y kernel panic (DoS).
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/25cdd2a492d868cff1e519a60fe282909c52d385
- https://git.kernel.org/stable/c/533d0c5feef85ee6404b9f41d5564fac6971a008
- https://git.kernel.org/stable/c/812f1db7f0755a19ef16ecdc5cec51bcabc5eda5
- https://git.kernel.org/stable/c/d665a1688af7f8fefd7c0eb04f2a37122ce007f4
- https://git.kernel.org/stable/c/dc77acfeb979dded39b247b60fef0399536bfa77
- https://git.kernel.org/stable/c/eb84cd81040e58dd05ac190f561f2115e3367249
- https://git.kernel.org/stable/c/f0eea8f9013676b42289ec35941e848b8a543e19
- https://git.kernel.org/stable/c/fda8fb7e8179561693a786a7af593f6b944a21c1
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-89777",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 8.8,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 6,
"exploitabilityScore": 2
}
]
},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
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],
"programFiles": [
"drivers/vfio/pci/vfio_pci_config.c"
],
"defaultStatus": "unaffected"
},
{
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"vendor": "Linux",
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},
{
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"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
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"version": "7.2.6",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/vfio/pci/vfio_pci_config.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-09-16T09:17:08.073",
"references": [
{
"url": "https://git.kernel.org/stable/c/25cdd2a492d868cff1e519a60fe282909c52d385",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/533d0c5feef85ee6404b9f41d5564fac6971a008",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/812f1db7f0755a19ef16ecdc5cec51bcabc5eda5",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/d665a1688af7f8fefd7c0eb04f2a37122ce007f4",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/dc77acfeb979dded39b247b60fef0399536bfa77",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/eb84cd81040e58dd05ac190f561f2115e3367249",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f0eea8f9013676b42289ec35941e848b8a543e19",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/fda8fb7e8179561693a786a7af593f6b944a21c1",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/pci: clear vdev->msi_perm after freeing it on init failure\n\nvfio_msi_cap_len() lazily allocates the per-device MSI permission table:\n\n\tvdev->msi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT);\n\tif (!vdev->msi_perm)\n\t\treturn -ENOMEM;\n\n\tret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags);\n\tif (ret) {\n\t\tkfree(vdev->msi_perm);\n\t\treturn ret;\t\t/* vdev->msi_perm left dangling */\n\t}\n\nWhen init_pci_cap_msi_perm() -> alloc_perm_bits() fails with -ENOMEM, the\nerror path frees vdev->msi_perm but leaves the freed pointer stored in\nit. vdev->msi_perm is not re-zeroed later because struct\nvfio_pci_core_device is per-device and persists across open/close cycles,\nand the vfio_config_init() error path returns without calling\nvfio_config_free(). So the dangling pointer outlives the failed open.\n\nThat leads to two use-after-frees on the same device:\n\n1. Reuse. The next vfio_config_init() sees the stale pointer at\n \"if (vdev->msi_perm) return len;\" and reuses the freed object. MSI\n config accesses in vfio_pci_config_rw_single() then dereference and\n call the freed perm->readfn / perm->writefn function pointers.\n\n2. Double free. A later vfio_config_free() runs free_perm_bits() and\n kfree() on the already-freed object.\n\nFix it by NULLing vdev->msi_perm after the kfree(), matching the\nNULL-after-free discipline already used in free_perm_bits() and\nvfio_config_free().\n\n BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)\n Read of size 8 at addr ffff88800fcc88d0 by task exploit/143\n Call Trace:\n ...\n kasan_report (mm/kasan/report.c:595)\n vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)\n vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986)\n vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599)\n vfs_read (fs/read_write.c:572)\n __x64_sys_pread64 (fs/read_write.c:764)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n ...\n\nFollowed on device close by a double free of the same object:\n\n Oops: general protection fault, probably for non-canonical address\n 0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI\n RIP: 0010:kfree (mm/slub.c:6711)\n Call Trace:\n vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861)\n vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685)\n vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777)\n vfio_df_close (drivers/vfio/vfio_main.c:602)\n vfio_device_fops_release (drivers/vfio/vfio_main.c:648)\n __fput (fs/file_table.c:512)\n __x64_sys_close (fs/open.c:1496)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n ...\n Kernel panic - not syncing: Fatal exception"
}
],
"lastModified": "2026-09-16T15:18:06.997",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}