{"id":"CVE-2026-63853","state":"PUBLISHED","title":"drm/amdgpu/vcn: set no_user_fence for VCN v4.0 enc ring","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu/vcn: set no_user_fence for VCN v4.0 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 fd852c048b46f9825e904a4f3f4538fe9d8827d9)","publishedAt":"2026-07-19T14:04:43.885Z","updatedAt":"2026-10-30T12:27:16.028Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"772f83fc70b797ac88d696671780eaf175cc7f31","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"525cc9df654365c147ae61e5562cf599ea2257f7","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"d8df8918677136b018d71d0b94a1f6b816715946","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"1286b6872de0aee1feeeaa6dbac86369806de9a5","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"6bdd2ed6458d35c368fbe9550a4d7f342abd3a92","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"51f694221047c84fa185be98210eb2c354ffb8c6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdgpu/vcn_v4_0.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.33","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.10","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdgpu/vcn_v4_0.c"]}],"references":["https://git.kernel.org/stable/c/772f83fc70b797ac88d696671780eaf175cc7f31","https://git.kernel.org/stable/c/525cc9df654365c147ae61e5562cf599ea2257f7","https://git.kernel.org/stable/c/d8df8918677136b018d71d0b94a1f6b816715946","https://git.kernel.org/stable/c/1286b6872de0aee1feeeaa6dbac86369806de9a5","https://git.kernel.org/stable/c/6bdd2ed6458d35c368fbe9550a4d7f342abd3a92","https://git.kernel.org/stable/c/51f694221047c84fa185be98210eb2c354ffb8c6"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-30T12:46:06.359Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63853.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63853","state":"PUBLISHED","datePublished":"2026-07-19T14:04:43.885Z","dateUpdated":"2026-10-30T12:27:16.028Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.016Z"},"containers":{"cna":{"title":"drm/amdgpu/vcn: set no_user_fence for VCN v4.0 enc ring","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 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 fd852c048b46f9825e904a4f3f4538fe9d8827d9)"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"772f83fc70b797ac88d696671780eaf175cc7f31","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"525cc9df654365c147ae61e5562cf599ea2257f7","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"d8df8918677136b018d71d0b94a1f6b816715946","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"1286b6872de0aee1feeeaa6dbac86369806de9a5","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"6bdd2ed6458d35c368fbe9550a4d7f342abd3a92","versionType":"git"},{"version":"8da1170a16e4d4b49fa07d1f75ad480847ff7eca","status":"affected","lessThan":"51f694221047c84fa185be98210eb2c354ffb8c6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdgpu/vcn_v4_0.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.33","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.10","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdgpu/vcn_v4_0.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/772f83fc70b797ac88d696671780eaf175cc7f31"},{"url":"https://git.kernel.org/stable/c/525cc9df654365c147ae61e5562cf599ea2257f7"},{"url":"https://git.kernel.org/stable/c/d8df8918677136b018d71d0b94a1f6b816715946"},{"url":"https://git.kernel.org/stable/c/1286b6872de0aee1feeeaa6dbac86369806de9a5"},{"url":"https://git.kernel.org/stable/c/6bdd2ed6458d35c368fbe9550a4d7f342abd3a92"},{"url":"https://git.kernel.org/stable/c/51f694221047c84fa185be98210eb2c354ffb8c6"}],"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 a crafted AMDGPU command stream through DRM_IOCTL_AMDGPU_CS on a local /dev/dri/renderD* device; there is no network, adjacent-radio, or physical-access path to the vulnerable VCN v4.0 unified encoder ring handling.\nAC:L - An attacker with render-node access can deterministically submit a CS containing an AMDGPU_CHUNK_ID_FENCE chunk targeting the VCN encoder ring; no race, special timing, or victim state beyond having a VCN 4.0-capable AMDGPU is required.\nPR:L - The path is reachable by any local user who can open the DRM render node (typically membership in the render/video group on desktops, workstations, and cloud GPU VMs); it does not require real root in the init namespace.\nUI:N - Triggering the bug is fully programmatic via ioctl-based CS submission and does not require any victim to open files, mount filesystems, or perform other interactive actions.\nS:U - Impact is confined to the AMDGPU/VCN driver and GPU resources of the submitting security context; it does not cross a VM, container, or IOMMU security boundary to affect a different authority.\nC:H - Without the no_user_fence guard, amdgpu_ib_commit emits a 64-bit user fence (AMDGPU_FENCE_FLAG_64BIT) on a ring whose emit_fence path only supports 32-bit fence writes, causing the VCN hardware to perform an unvalidated GPU DMA write that can corrupt adjacent GPU-mapped memory and be leveraged for information disclosure.\nI:H - The same rogue GPU-initiated fence write is a memory-corruption primitive that can modify GPU-accessible buffers (including shared dma-buf mappings) outside the intended 8-byte fence field, enabling integrity violations and potential further exploitation.\nA:H - Malformed fence/trap commands on the VCN unified encoder ring can hang or fault the VCN block and force GPU/driver reset, denying graphics and compute availability to all users of the device on shared workstations and servers."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:27:16.028Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.18.33"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"7.0.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-63853","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:32:17.901838Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","type":"CWE","description":"CWE-20 Improper Input Validation"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:07:51.666Z"}}]}}}