CVE-2026-31699

Estado: ModificadaAlta (7.1)—

In the Linux kernel, the following vulnerability has been resolved:

crypto: ccp: Don't attempt to copy CSR to userspace if PSP command failed

When retrieving the PEK CSR, don't attempt to copy the blob to userspace if the firmware command failed. If the failure was due to an invalid length, i.e. the userspace buffer+length was too small, copying the number of bytes _firmware_ requires will overflow the kernel-allocated buffer and leak data to userspace.

WARN if the driver says the command succeeded, but the firmware error code says otherwise, as __sev_do_cmd_locked() is expected to return -EIO on any firwmware error.

Detalles técnicos trazas, registros y código del informe original

  BUG: KASAN: slab-out-of-bounds in instrument_copy_to_user ../include/linux/instrumented.h:129 [inline]
  BUG: KASAN: slab-out-of-bounds in _inline_copy_to_user ../include/linux/uaccess.h:205 [inline]
  BUG: KASAN: slab-out-of-bounds in _copy_to_user+0x66/0xa0 ../lib/usercopy.c:26
  Read of size 2084 at addr ffff898144612e20 by task syz.9.219/21405

  CPU: 14 UID: 0 PID: 21405 Comm: syz.9.219 Tainted: G     U     O        7.0.0-smp-DEV #28 PREEMPTLAZY
  Tainted: [U]=USER, [O]=OOT_MODULE
  Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 12.62.0-0 11/19/2025
  Call Trace:
   <TASK>
   dump_stack_lvl+0xc5/0x110 ../lib/dump_stack.c:120
   print_address_description ../mm/kasan/report.c:378 [inline]
   print_report+0xbc/0x260 ../mm/kasan/report.c:482
   kasan_report+0xa2/0xe0 ../mm/kasan/report.c:595
   check_region_inline ../mm/kasan/generic.c:-1 [inline]
   kasan_check_range+0x264/0x2c0 ../mm/kasan/generic.c:200
   instrument_copy_to_user ../include/linux/instrumented.h:129 [inline]
   _inline_copy_to_user ../include/linux/uaccess.h:205 [inline]
   _copy_to_user+0x66/0xa0 ../lib/usercopy.c:26
   copy_to_user ../include/linux/uaccess.h:236 [inline]
   sev_ioctl_do_pek_csr+0x31f/0x590 ../drivers/crypto/ccp/sev-dev.c:1872
   sev_ioctl+0x3a4/0x490 ../drivers/crypto/ccp/sev-dev.c:2562
   vfs_ioctl ../fs/ioctl.c:51 [inline]
   __do_sys_ioctl ../fs/ioctl.c:597 [inline]
   __se_sys_ioctl+0x11d/0x1b0 ../fs/ioctl.c:583
   do_syscall_x64 ../arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0xe0/0x800 ../arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x76/0x7e
   </TASK>

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Puntuación base: 7.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.17%
Percentil entre todas las CVEs puntuadas: 5
Fecha de la puntuación: 6/10/2026

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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation75 %
Impacto principalT1005 Data from Local Systemcollection80 %
Impacto secundarioT1552 Unsecured Credentialscredential access75 %

Vulnerabilidad local de buffer overflow (CWE-787) en ioctl sin interacción de usuario. Impacto: lectura de datos del kernel y fuga de información sensible en memoria mediante copy_to_user sin validación.

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

Update Software Active Directory Configuration User Training Threat Intelligence Program Restrict File and Directory Permissions Privileged Account Management

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-787

Referencias

JSON original (NVD)

Mostrar

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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: ccp: Don't attempt to copy CSR to userspace if PSP command failed\n\nWhen retrieving the PEK CSR, don't attempt to copy the blob to userspace\nif the firmware command failed.  If the failure was due to an invalid\nlength, i.e. the userspace buffer+length was too small, copying the number\nof bytes _firmware_ requires will overflow the kernel-allocated buffer and\nleak data to userspace.\n\n  BUG: KASAN: slab-out-of-bounds in instrument_copy_to_user ../include/linux/instrumented.h:129 [inline]\n  BUG: KASAN: slab-out-of-bounds in _inline_copy_to_user ../include/linux/uaccess.h:205 [inline]\n  BUG: KASAN: slab-out-of-bounds in _copy_to_user+0x66/0xa0 ../lib/usercopy.c:26\n  Read of size 2084 at addr ffff898144612e20 by task syz.9.219/21405\n\n  CPU: 14 UID: 0 PID: 21405 Comm: syz.9.219 Tainted: G     U     O        7.0.0-smp-DEV #28 PREEMPTLAZY\n  Tainted: [U]=USER, [O]=OOT_MODULE\n  Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 12.62.0-0 11/19/2025\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0xc5/0x110 ../lib/dump_stack.c:120\n   print_address_description ../mm/kasan/report.c:378 [inline]\n   print_report+0xbc/0x260 ../mm/kasan/report.c:482\n   kasan_report+0xa2/0xe0 ../mm/kasan/report.c:595\n   check_region_inline ../mm/kasan/generic.c:-1 [inline]\n   kasan_check_range+0x264/0x2c0 ../mm/kasan/generic.c:200\n   instrument_copy_to_user ../include/linux/instrumented.h:129 [inline]\n   _inline_copy_to_user ../include/linux/uaccess.h:205 [inline]\n   _copy_to_user+0x66/0xa0 ../lib/usercopy.c:26\n   copy_to_user ../include/linux/uaccess.h:236 [inline]\n   sev_ioctl_do_pek_csr+0x31f/0x590 ../drivers/crypto/ccp/sev-dev.c:1872\n   sev_ioctl+0x3a4/0x490 ../drivers/crypto/ccp/sev-dev.c:2562\n   vfs_ioctl ../fs/ioctl.c:51 [inline]\n   __do_sys_ioctl ../fs/ioctl.c:597 [inline]\n   __se_sys_ioctl+0x11d/0x1b0 ../fs/ioctl.c:583\n   do_syscall_x64 ../arch/x86/entry/syscall_64.c:63 [inline]\n   do_syscall_64+0xe0/0x800 ../arch/x86/entry/syscall_64.c:94\n   entry_SYSCALL_64_after_hwframe+0x76/0x7e\n   </TASK>\n\nWARN if the driver says the command succeeded, but the firmware error code\nsays otherwise, as __sev_do_cmd_locked() is expected to return -EIO on any\nfirwmware error."
    }
  ],
  "lastModified": "2026-06-17T10:34:15.920",
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