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VulnerabilityAwaiting classification

CVE-2026-63885

HIGH · 8.8 CVSS v3.1 Published 2026-07-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
90/100
Remediation priority · Urgent
Zero-click 5 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: drm/gem: fix race between change_handle and handle_delete drm_gem_change_handle_ioctl leaves the old handle live in the IDR during the window between spin_unlock(table_lock) and the final spin_lock(table_lock). A concurrent drm_gem_handle_delete on the old handle succeeds in this window, decrements handle_count to 0, and frees the GEM object while the new handle's IDR entry still references it. NULL the old handle's IDR entry before dropping table_lock so that any concurrent GEM_CLOSE on the old handle sees NULL and returns -EINVAL. Restore the old entry on the prime-bookkeeping error path.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A race condition in drm_gem_change_handle_ioctl leaves the old handle's IDR entry live during a window between spin_unlock and spin_lock. A concurrent handle_delete can free the GEM object while the new handle still references it, causing a use-after-free. The fix nulls the old IDR entry before releasing the lock so concurrent operations see NULL and return -EINVAL.

MitigationApply the kernel patch to null the IDR entry before releasing table_lock. This is a source-code level fix requiring kernel rebuild. Prioritize on systems running DRM workloads with frequent handle operations.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify kernel version
    Run 'uname -r' to get the running kernel version
    Affected if The kernel version is older than the version that includes the CVE-2026-63885 fix in the DRM subsystem
  2. Locate the drm_gem_change_handle_ioctl source file
    Find the file containing drm_gem_change_handle_ioctl in the kernel source, typically in drivers/gpu/drm/ - often drm_gem.c or within the specific DRM driver
    Affected if The source file does not contain the nulling fix for the old handle's IDR entry before dropping table_lock
  3. Inspect the race condition window in the code
    Search the drm_gem source for the pattern: look for the code block between table_lock unlock and re-lock where old handle IDR removal occurs, verify if it sets the old handle IDR entry to NULL before the unlock
    Affected if The code shows a gap where drm_gem_handle_delete could free the object while the new handle's IDR entry still references it (old handle not set to NULL before unlock)
  4. Check if DRM/GEM subsystem is in use
    Run 'lsmod | grep drm' or check /sys/class/drm/ to see if DRM modules are loaded
    Affected if No DRM modules are loaded, then the vulnerable code path cannot be triggered
  5. Verify concurrent handle operations can occur
    Examine if userspace applications can issue DRM_IOCTL_GEM_CHANGE_HANDLE and DRM_IOCTL_GEM_CLOSE ioctls concurrently against the same GEM object
    Affected if The environment allows concurrent GEM handle changes and deletions on the same object, enabling the race condition

A system is affected if it runs a kernel version lacking the CVE-2026-63885 fix, has the DRM subsystem active, and can trigger concurrent drm_gem_change_handle_ioctl and drm_gem_handle_delete operations on the same GEM object.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the kernel patch to null the IDR entry before releasing table_lock. This is a source-code level fix requiring kernel rebuild. Prioritize on systems running DRM workloads with frequent handle operations.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,020
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-63885 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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