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CVE-2026-63863 (GCVE-0-2026-63863)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:04 – Updated: 2026-08-05 12:36
VLAI
Title
drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm()
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm() There is a unbalanced lock/unlock to gpusvm notifier lock: [ 931.045868] ===================================== [ 931.046509] WARNING: bad unlock balance detected! [ 931.047149] 6.19.0-rc6+xe-**************** #9 Tainted: G U [ 931.048150] ------------------------------------- [ 931.048790] kworker/u5:0/51 is trying to release lock (&gpusvm->notifier_lock) at: [ 931.049801] [<ffffffffa090c0d8>] drm_gpusvm_scan_mm+0x188/0x460 [drm_gpusvm_helper] [ 931.050802] but there are no more locks to release! [ 931.051463] The drm_gpusvm_notifier_unlock() sits under err_free label and the first jump to err_free is just before calling the drm_gpusvm_notifier_lock() causing unbalanced unlock.
Severity
8.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f1d08a5864822684773105c60528e2abb577ca6c , < 8efaa47a871662a8c21b819cec60786f7ef17ab4 (git)
Affected: f1d08a5864822684773105c60528e2abb577ca6c , < d287dee565c3c32e1ed76ec1847af46809c29b90 (git)
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Linux Linux Affected: 7.0
Unaffected: 0 , < 7.0 (semver)
Unaffected: 7.0.10 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
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        }
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      "metrics": [
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            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable code is only reached via Intel Xe DRM ioctls (DRM_XE_VM_BIND prefetch, GPU page-fault handling) on /dev/dri/renderD*, which require local access to the GPU device node.\nAC:L - An attacker can reliably trigger the bug by racing CPU memory operations (munmap/mremap/mprotect) against GPU SVM VRAM migration to force hmm_range_fault() to return an error or time out on -EBUSY, hitting the err_free path without holding notifier_lock.\nPR:L - Exploitation requires opening the DRM render node (DRM_RENDER_ALLOW), which is available to unprivileged users in the render group on typical desktop and cloud GPU instances, not root or capabilities.\nUI:N - No victim interaction is required; the attacker triggers the condition through their own GPU VM bindings, compute submissions, and concurrent memory manipulation.\nS:C - Corrupting notifier_lock breaks the documented IOMMU security model for GPU SVM, allowing GPU DMA operations to proceed without proper invalidation synchronization and potentially accessing host memory outside the attacker\u0027s GPU context.\nC:H - Rwsem corruption from the spurious unlock can desynchronize invalidation from migration, enabling races where the GPU reads stale or freed pages that may have been reallocated, constituting arbitrary memory disclosure.\nI:H - The same lock corruption can allow GPU DMA writes to pages during or after invalidation races, providing a path to arbitrary memory corruption and potential privilege escalation.\nA:H - The bug triggers a kernel lockdep warning (\"bad unlock balance detected\") and rwsem corruption can cause kernel oops, hangs, or panic during subsequent notifier_lock operations."
            }
          ]
        }
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      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:39.194Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/d287dee565c3c32e1ed76ec1847af46809c29b90"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63863",
    "datePublished": "2026-07-19T14:04:49.967Z",
    "dateReserved": "2026-07-19T07:54:57.017Z",
    "dateUpdated": "2026-08-05T12:36:39.194Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-21T19:05:56+00:00",
      "cve": "CVE-2026-63863",
      "id": "CVE-2026-63863",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "108",
      "product_status:known_not_affected": "166",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63863.json",
      "version": "3"
    }
  }
}



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