Local GPU memory corruption via unsupported user fences
Published Jul 19, 2026 · Updated Jul 19, 2026
Memory corruption in the AMDGPU VCN v5.0.1 encoder in Linux Kernel allows local users to write GPU memory via crafted commands. The vcn_v5_0_1_unified_ring_vm_funcs table leaves no_user_fence unset, so DRM_IOCTL_AMDGPU_CS accepts AMDGPU_CHUNK_ID_FENCE on a ring that cannot perform 64-bit user-fence writes. Access to an AMDGPU render node and affected VCN 5.0.1 hardware is required; corruption can disclose data, alter buffers, or hang or reset the GPU.
Summary
What happened
Memory corruption in the AMDGPU VCN v5.0.1 encoder in Linux Kernel allows local users to write GPU memory via crafted commands. The vcn_v5_0_1_unified_ring_vm_funcs table leaves no_user_fence unset, so DRM_IOCTL_AMDGPU_CS accepts AMDGPU_CHUNK_ID_FENCE on a ring that cannot perform 64-bit user-fence writes. Access to an AMDGPU render node and affected VCN 5.0.1 hardware is required; corruption can disclose data, alter buffers, or hang or reset the GPU.
The record
- CVE
- CVE-2026-63849
- Published
- Jul 19, 2026
- Updated
- Jul 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 19, 2026CVE publishedPublication date reported by the CVE source.
- Jul 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=346492f30ce3581bf5324c4ae417eab8537dc998 <081ef0e46c9cdd26c0db0ef721470393d36b6655
- Affected versionversion=346492f30ce3581bf5324c4ae417eab8537dc998 <5a4bffd67e94944ed3db26a959346cfb7fabaecd
- Affected versionversion=346492f30ce3581bf5324c4ae417eab8537dc998 <8f4954722eab88e10c4ea0c0d3b1269c31421d3a
- Affected versionversion=6.14
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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Your stack
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