CVE-2026-45878
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix watch_id bounds checking in debug address watch v2
The address watch clear code receives watch_id as an unsigned value (u32), but some helper functions were using a signed int and checked bits by shifting with watch_id.
If a very large watch_id is passed from userspace, it can be converted to a negative value. This can cause invalid shifts and may access memory outside the watch_points array.
drm/amdkfd: Fix watch_id bounds checking in debug address watch v2
Fix this by checking that watch_id is within MAX_WATCH_ADDRESSES before using it. Also use BIT(watch_id) to test and clear bits safely.
Leer descripción completaMostrar menos
This keeps the behavior unchanged for valid watch IDs and avoids undefined behavior for invalid ones.
Fixes the below: drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c:448 kfd_dbg_trap_clear_dev_address_watch() error: buffer overflow 'pdd->watch_points' 4 <= u32max user_rl='0-3,2147483648-u32max' uncapped
kfd_dbg_owns_dev_watch_id() doesn't check for negative values so if watch_id is larger than INT_MAX it leads to a buffer overflow. (Negative shifts are undefined).
v2: (as per, Jonathan Kim) - Add early watch_id >= MAX_WATCH_ADDRESSES validation in the set path to match the clear path. - Drop the redundant bounds check in kfd_dbg_owns_dev_watch_id().
Detalles técnicos trazas, registros y código del informe original
drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c
433 int kfd_dbg_trap_clear_dev_address_watch(struct kfd_process_device *pdd,
434 uint32_t watch_id)
435 {
436 int r;
437
438 if (!kfd_dbg_owns_dev_watch_id(pdd, watch_id))
439 return -EINVAL;
440
441 if (!pdd->dev->kfd->shared_resources.enable_mes) {
442 r = debug_lock_and_unmap(pdd->dev->dqm);
443 if (r)
444 return r;
445 }
446
447 amdgpu_gfx_off_ctrl(pdd->dev->adev, false);
--> 448 pdd->watch_points[watch_id] = pdd->dev->kfd2kgd->clear_address_watch(
449 pdd->dev->adev,
450 watch_id);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: 0.18%
- Percentil entre todas las CVEs puntuadas: 7
- 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 escalation90 % - Impacto principal
T1005Data from Local Systemcollection75 % - Impacto secundario
T1499.004Application or System Exploitationimpact60 %
Acceso local sin interacción (AV:L/PR:L/UI:N) permite escalada de privilegios explotando desbordamiento de búfer en validación de watch_id, causando acceso no autorizado a memoria kernel y potencial denegación de servicio.
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)
CWE
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/2b36c0c1bcbbe15f6cfa9652084b3124c835a150
- https://git.kernel.org/stable/c/3c38a0f07aa2bfef2b219b1f045534ad93f85afd
- https://git.kernel.org/stable/c/5a19302cab5cec7ae7f1a60c619951e6c17d8742
- https://git.kernel.org/stable/c/971bf8e61e9b4abaacf9b35eaf76ec222758f9d6
- https://git.kernel.org/stable/c/a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdkfd: Fix watch_id bounds checking in debug address watch v2\n\nThe address watch clear code receives watch_id as an unsigned value\n(u32), but some helper functions were using a signed int and checked\nbits by shifting with watch_id.\n\nIf a very large watch_id is passed from userspace, it can be converted\nto a negative value. This can cause invalid shifts and may access\nmemory outside the watch_points array.\n\ndrm/amdkfd: Fix watch_id bounds checking in debug address watch v2\n\nFix this by checking that watch_id is within MAX_WATCH_ADDRESSES before\nusing it. Also use BIT(watch_id) to test and clear bits safely.\n\nThis keeps the behavior unchanged for valid watch IDs and avoids\nundefined behavior for invalid ones.\n\nFixes the below:\ndrivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c:448\nkfd_dbg_trap_clear_dev_address_watch() error: buffer overflow\n'pdd->watch_points' 4 <= u32max user_rl='0-3,2147483648-u32max' uncapped\n\ndrivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c\n 433 int kfd_dbg_trap_clear_dev_address_watch(struct kfd_process_device *pdd,\n 434 uint32_t watch_id)\n 435 {\n 436 int r;\n 437\n 438 if (!kfd_dbg_owns_dev_watch_id(pdd, watch_id))\n\nkfd_dbg_owns_dev_watch_id() doesn't check for negative values so if\nwatch_id is larger than INT_MAX it leads to a buffer overflow.\n(Negative shifts are undefined).\n\n 439 return -EINVAL;\n 440\n 441 if (!pdd->dev->kfd->shared_resources.enable_mes) {\n 442 r = debug_lock_and_unmap(pdd->dev->dqm);\n 443 if (r)\n 444 return r;\n 445 }\n 446\n 447 amdgpu_gfx_off_ctrl(pdd->dev->adev, false);\n--> 448 pdd->watch_points[watch_id] = pdd->dev->kfd2kgd->clear_address_watch(\n 449 pdd->dev->adev,\n 450 watch_id);\n\nv2: (as per, Jonathan Kim)\n - Add early watch_id >= MAX_WATCH_ADDRESSES validation in the set path to\n match the clear path.\n - Drop the redundant bounds check in kfd_dbg_owns_dev_watch_id()."
}
],
"lastModified": "2026-06-25T21:12:02.230",
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