CVE-2025-68810
Estado: AplazadaAlta (7.8)—
In the Linux kernel, the following vulnerability has been resolved:
KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot
Reject attempts to disable KVM_MEM_GUEST_MEMFD on a memslot that was initially created with a guest_memfd binding, as KVM doesn't support toggling KVM_MEM_GUEST_MEMFD on existing memslots. KVM prevents enabling KVM_MEM_GUEST_MEMFD, but doesn't prevent clearing the flag.
Failure to reject the new memslot results in a use-after-free due to KVM not unbinding from the guest_memfd instance. Unbinding on a FLAGS_ONLY change is easy enough, and can/will be done as a hardening measure (in anticipation of KVM supporting dirty logging on guest_memfd at some point), but fixing the use-after-free would only address the immediate symptom.
Detalles técnicos trazas, registros y código del informe original
================================================================== BUG: KASAN: slab-use-after-free in kvm_gmem_release+0x362/0x400 [kvm] Write of size 8 at addr ffff8881111ae908 by task repro/745 CPU: 7 UID: 1000 PID: 745 Comm: repro Not tainted 6.18.0-rc6-115d5de2eef3-next-kasan #3 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl+0x51/0x60 print_report+0xcb/0x5c0 kasan_report+0xb4/0xe0 kvm_gmem_release+0x362/0x400 [kvm] __fput+0x2fa/0x9d0 task_work_run+0x12c/0x200 do_exit+0x6ae/0x2100 do_group_exit+0xa8/0x230 __x64_sys_exit_group+0x3a/0x50 x64_sys_call+0x737/0x740 do_syscall_64+0x5b/0x900 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f581f2eac31 </TASK> Allocated by task 745 on cpu 6 at 9.746971s: kasan_save_stack+0x20/0x40 kasan_save_track+0x13/0x50 __kasan_kmalloc+0x77/0x90 kvm_set_memory_region.part.0+0x652/0x1110 [kvm] kvm_vm_ioctl+0x14b0/0x3290 [kvm] __x64_sys_ioctl+0x129/0x1a0 do_syscall_64+0x5b/0x900 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Freed by task 745 on cpu 6 at 9.747467s: kasan_save_stack+0x20/0x40 kasan_save_track+0x13/0x50 __kasan_save_free_info+0x37/0x50 __kasan_slab_free+0x3b/0x60 kfree+0xf5/0x440 kvm_set_memslot+0x3c2/0x1160 [kvm] kvm_set_memory_region.part.0+0x86a/0x1110 [kvm] kvm_vm_ioctl+0x14b0/0x3290 [kvm] __x64_sys_ioctl+0x129/0x1a0 do_syscall_64+0x5b/0x900 entry_SYSCALL_64_after_hwframe+0x4b/0x53
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: 0.14%
- Percentil entre todas las CVEs puntuadas: 3
- 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 escalation95 % - Impacto principal
T1499.004Application or System Exploitationimpact85 % - Impacto secundario
T1005Data from Local Systemcollection70 %
Vulnerabilidad local de use-after-free en KVM (AV:L, PR:L) que permite a un usuario local provocar DoS o potencial lectura de datos en memoria del kernel mediante manipulación de memslots.
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
JSON original (NVD)
Mostrar
{
"id": "CVE-2025-68810",
"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": "a7800aa80ea4d5356b8474c2302812e9d4926fa6",
"lessThan": "89dbbe6ff323fc34659621a577fe0af913f47386",
"versionType": "git"
},
{
"status": "affected",
"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6",
"lessThan": "cb51bef465d8ec60a968507330e01020e35dc127",
"versionType": "git"
},
{
"status": "affected",
"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6",
"lessThan": "9935df5333aa503a18de5071f53762b65c783c4c",
"versionType": "git"
}
],
"programFiles": [
"virt/kvm/kvm_main.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.64",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.3",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"virt/kvm/kvm_main.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-01-13T16:16:03.190",
"references": [
{
"url": "https://git.kernel.org/stable/c/89dbbe6ff323fc34659621a577fe0af913f47386",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/9935df5333aa503a18de5071f53762b65c783c4c",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/cb51bef465d8ec60a968507330e01020e35dc127",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Deferred",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot\n\nReject attempts to disable KVM_MEM_GUEST_MEMFD on a memslot that was\ninitially created with a guest_memfd binding, as KVM doesn't support\ntoggling KVM_MEM_GUEST_MEMFD on existing memslots. KVM prevents enabling\nKVM_MEM_GUEST_MEMFD, but doesn't prevent clearing the flag.\n\nFailure to reject the new memslot results in a use-after-free due to KVM\nnot unbinding from the guest_memfd instance. Unbinding on a FLAGS_ONLY\nchange is easy enough, and can/will be done as a hardening measure (in\nanticipation of KVM supporting dirty logging on guest_memfd at some point),\nbut fixing the use-after-free would only address the immediate symptom.\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in kvm_gmem_release+0x362/0x400 [kvm]\n Write of size 8 at addr ffff8881111ae908 by task repro/745\n\n CPU: 7 UID: 1000 PID: 745 Comm: repro Not tainted 6.18.0-rc6-115d5de2eef3-next-kasan #3 NONE\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n Call Trace:\n <TASK>\n dump_stack_lvl+0x51/0x60\n print_report+0xcb/0x5c0\n kasan_report+0xb4/0xe0\n kvm_gmem_release+0x362/0x400 [kvm]\n __fput+0x2fa/0x9d0\n task_work_run+0x12c/0x200\n do_exit+0x6ae/0x2100\n do_group_exit+0xa8/0x230\n __x64_sys_exit_group+0x3a/0x50\n x64_sys_call+0x737/0x740\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n RIP: 0033:0x7f581f2eac31\n </TASK>\n\n Allocated by task 745 on cpu 6 at 9.746971s:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x13/0x50\n __kasan_kmalloc+0x77/0x90\n kvm_set_memory_region.part.0+0x652/0x1110 [kvm]\n kvm_vm_ioctl+0x14b0/0x3290 [kvm]\n __x64_sys_ioctl+0x129/0x1a0\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n Freed by task 745 on cpu 6 at 9.747467s:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x13/0x50\n __kasan_save_free_info+0x37/0x50\n __kasan_slab_free+0x3b/0x60\n kfree+0xf5/0x440\n kvm_set_memslot+0x3c2/0x1160 [kvm]\n kvm_set_memory_region.part.0+0x86a/0x1110 [kvm]\n kvm_vm_ioctl+0x14b0/0x3290 [kvm]\n __x64_sys_ioctl+0x129/0x1a0\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53"
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nKVM: No permitir la alternancia de KVM_MEM_GUEST_MEMFD en un memslot existente\n\nRechazar los intentos de deshabilitar KVM_MEM_GUEST_MEMFD en un memslot que fue creado inicialmente con una vinculación guest_memfd, ya que KVM no soporta la alternancia de KVM_MEM_GUEST_MEMFD en memslots existentes. KVM impide habilitar KVM_MEM_GUEST_MEMFD, pero no impide borrar el indicador.\n\nLa falta de rechazo del nuevo memslot resulta en un uso después de liberación debido a que KVM no se desvincula de la instancia guest_memfd. La desvinculación en un cambio de FLAGS_ONLY es bastante sencilla, y puede/será realizada como una medida de endurecimiento (en anticipación de que KVM soporte el registro de cambios (dirty logging) en guest_memfd en algún momento), pero corregir el uso después de liberación solo abordaría el síntoma inmediato.\n\n ==================================================================\n ERROR: KASAN: uso después de liberación de slab en kvm_gmem_release+0x362/0x400 [kvm]\n Escritura de tamaño 8 en la dirección ffff8881111ae908 por la tarea repro/745\n\n CPU: 7 UID: 1000 PID: 745 Comm: repro No contaminado 6.18.0-rc6-115d5de2eef3-next-kasan #3 NINGUNO\n Nombre del hardware: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n Traza de llamada:\n \n dump_stack_lvl+0x51/0x60\n print_report+0xcb/0x5c0\n kasan_report+0xb4/0xe0\n kvm_gmem_release+0x362/0x400 [kvm]\n __fput+0x2fa/0x9d0\n task_work_run+0x12c/0x200\n do_exit+0x6ae/0x2100\n do_group_exit+0xa8/0x230\n __x64_sys_exit_group+0x3a/0x50\n x64_sys_call+0x737/0x740\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n RIP: 0033:0x7f581f2eac31\n \n\n Asignado por la tarea 745 en la CPU 6 a las 9.746971s:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x13/0x50\n __kasan_kmalloc+0x77/0x90\n kvm_set_memory_region.part.0+0x652/0x1110 [kvm]\n kvm_vm_ioctl+0x14b0/0x3290 [kvm]\n __x64_sys_ioctl+0x129/0x1a0\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n Liberado por la tarea 745 en la CPU 6 a las 9.747467s:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x13/0x50\n __kasan_save_free_info+0x37/0x50\n __kasan_slab_free+0x3b/0x60\n kfree+0xf5/0x440\n kvm_set_memslot+0x3c2/0x1160 [kvm]\n kvm_set_memory_region.part.0+0x86a/0x1110 [kvm]\n kvm_vm_ioctl+0x14b0/0x3290 [kvm]\n __x64_sys_ioctl+0x129/0x1a0\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53"
}
],
"lastModified": "2026-07-30T06:24:46.630",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}