{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63851","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.016Z","datePublished":"2026-07-19T14:04:42.581Z","dateUpdated":"2026-08-05T12:36:29.527Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:36:29.527Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu/vcn: set no_user_fence for VCN v4.0.5 enc ring\n\nVCN encoder and decoder rings do not support 64-bit user fence writes,\nreject CS submissions with user fences.\n\n(cherry picked from commit 084d94ac93707bdda07efb5cee786f632de4219b)"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires submitting AMDGPU command streams via the DRM render node (DRM_IOCTL_AMDGPU_CS), which is a local ioctl/device-file interface with no network-facing entry point.\nAC:L - An attacker with render-node access can deterministically craft a CS submission with a FENCE chunk targeting the VCN_ENC ring; no race conditions or attacker-uncontrollable timing are required.\nPR:L - The only gate is access to /dev/dri/renderD* (DRM_AUTH|DRM_RENDER_ALLOW), which is available to unprivileged local users in the render/video group and does not require root or capabilities obtainable only in the init namespace.\nUI:N - Once the attacker has render-node access, triggering the bug requires no additional victim interaction beyond normal GPU command submission.\nS:U - Impact is confined to the same local security domain (kernel/GPU driver); exploitation does not cross a VM, container, or IOMMU security boundary to a different authority.\nC:H - The unsupported GPU fence operation causes the VCN hardware to perform DMA writes outside the driver's validated semantics, creating a memory-corruption primitive that could expose or corrupt GPU-mapped memory beyond the intended 8-byte fence slot.\nI:H - The bug enables GPU-initiated writes to attacker-chosen GPU virtual addresses (user fence buffer), and hardware misbehavior on unsupported fence commands can corrupt adjacent or shared dma-buf memory with unpredictable write patterns.\nA:H - Submitting unsupported user fences to the VCN ring can hang the GPU, trigger VCN poison/RAS interrupts, or crash the graphics subsystem, causing denial of service on affected systems."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdgpu/vcn_v4_0_5.c"],"versions":[{"version":"547aad32edac17a3ec4989d8aad2426d0cbeb590","lessThan":"75091030f07b7957cc0646cd52e2d9d15f611483","status":"affected","versionType":"git"},{"version":"547aad32edac17a3ec4989d8aad2426d0cbeb590","lessThan":"6d9a98c5ed65ba92a09e4ca5a5f6941448145529","status":"affected","versionType":"git"},{"version":"547aad32edac17a3ec4989d8aad2426d0cbeb590","lessThan":"7f23b5c420b9f68a210c29c5123bace670aa8cc9","status":"affected","versionType":"git"},{"version":"547aad32edac17a3ec4989d8aad2426d0cbeb590","lessThan":"589a254bf3e88204c8402b9cbccd5e23a0af990f","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdgpu/vcn_v4_0_5.c"],"versions":[{"version":"6.7","status":"affected"},{"version":"0","lessThan":"6.7","status":"unaffected","versionType":"semver"},{"version":"6.12.91","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.33","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.10","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.91"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.18.33"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.0.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/75091030f07b7957cc0646cd52e2d9d15f611483"},{"url":"https://git.kernel.org/stable/c/6d9a98c5ed65ba92a09e4ca5a5f6941448145529"},{"url":"https://git.kernel.org/stable/c/7f23b5c420b9f68a210c29c5123bace670aa8cc9"},{"url":"https://git.kernel.org/stable/c/589a254bf3e88204c8402b9cbccd5e23a0af990f"}],"title":"drm/amdgpu/vcn: set no_user_fence for VCN v4.0.5 enc ring","x_generator":{"engine":"bippy-1.2.0"}}}}