CVE-2026-45878

Full vulnerability record from the local CVENow database.

Description

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. 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 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)) 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). 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); 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().

Severity

HIGH

CVSS score

7.8 (v3.1)

Vulnerability status

Modified

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-05-27 14:17:01.547000

Last modified

2026-10-19 20:18:20.693000

View original CVE JSON

{
  "id": "CVE-2026-45878",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-05-27T14:17:01.547",
  "lastModified": "2026-10-19T20:18:20.693",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "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()."
    }
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          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
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        "ssvcData": {
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          "id": "CVE-2026-45878",
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