{"id":"CVE-2026-63852","state":"PUBLISHED","title":"drm/amdgpu/vcn: set no_user_fence for VCN v4.0.3 enc ring","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu/vcn: set no_user_fence for VCN v4.0.3 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 ff1a5a125c5a70c328806b9bc01d7d942cf3f9aa)","publishedAt":"2026-07-19T14:04:43.258Z","updatedAt":"2026-10-19T20:07:51.529Z","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":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"c12a5d35033c0640c57c10d7111c010c7b9c2c8e","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"387b7c7667bd5c53549350ddad866d2fcf75a529","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"9076a83e5adefd10dc5c967c7b8bde601c4c512a","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"0177ac6141c8857130cf365369c74dee7b6b1f7f","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"4532b52b34e4e4310386e6fdf6a643368599f522","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.5","versionType":"semver"},{"version":"6.6.141","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.91","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_3.c"]}],"references":["https://git.kernel.org/stable/c/c12a5d35033c0640c57c10d7111c010c7b9c2c8e","https://git.kernel.org/stable/c/387b7c7667bd5c53549350ddad866d2fcf75a529","https://git.kernel.org/stable/c/9076a83e5adefd10dc5c967c7b8bde601c4c512a","https://git.kernel.org/stable/c/0177ac6141c8857130cf365369c74dee7b6b1f7f","https://git.kernel.org/stable/c/4532b52b34e4e4310386e6fdf6a643368599f522"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63852.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63852","state":"PUBLISHED","datePublished":"2026-07-19T14:04:43.258Z","dateUpdated":"2026-10-19T20:07:51.529Z","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 v4.0.3 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 v4.0.3 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 ff1a5a125c5a70c328806b9bc01d7d942cf3f9aa)"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"c12a5d35033c0640c57c10d7111c010c7b9c2c8e","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"387b7c7667bd5c53549350ddad866d2fcf75a529","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"9076a83e5adefd10dc5c967c7b8bde601c4c512a","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"0177ac6141c8857130cf365369c74dee7b6b1f7f","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","status":"affected","lessThan":"4532b52b34e4e4310386e6fdf6a643368599f522","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.5","versionType":"semver"},{"version":"6.6.141","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.91","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_3.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c12a5d35033c0640c57c10d7111c010c7b9c2c8e"},{"url":"https://git.kernel.org/stable/c/387b7c7667bd5c53549350ddad866d2fcf75a529"},{"url":"https://git.kernel.org/stable/c/9076a83e5adefd10dc5c967c7b8bde601c4c512a"},{"url":"https://git.kernel.org/stable/c/0177ac6141c8857130cf365369c74dee7b6b1f7f"},{"url":"https://git.kernel.org/stable/c/4532b52b34e4e4310386e6fdf6a643368599f522"}],"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 - The vulnerable code is reached only through DRM_IOCTL_AMDGPU_CS on an AMDGPU render node (/dev/dri/renderD*), requiring a local ioctl from userspace to submit command streams with a user fence chunk to the VCN v4.0.3 unified encoder ring.\nAC:L - On affected VCN 4.0.3 hardware, an attacker fully controls CS submission parameters (fence GEM handle, offset, and VCN_ENC ring IB) and can reliably trigger the unsupported 64-bit user fence path without races or external timing dependencies.\nPR:L - DRM_IOCTL_AMDGPU_CS is gated by DRM_AUTH|DRM_RENDER_ALLOW, so any unprivileged local user with render-node access (typically membership in the render group) can reach the vulnerable path without root or special capabilities.\nUI:N - Exploitation requires only programmatic ioctl submission; no victim interaction such as opening files, mounting filesystems, or clicking prompts is needed.\nS:U - The flaw enables GPU-initiated memory corruption within the attacker's own AMDGPU context/VM via the render node, which is a standard local kernel/GPU-driver privilege boundary rather than a cross-authority escape such as VM guest-to-host or IOMMU bypass.\nC:H - Submitting a 64-bit user fence to a ring that only supports 32-bit fence writes causes the VCN hardware to perform misdirected or out-of-bounds GPU memory writes, providing a memory-corruption primitive that can be leveraged for information disclosure.\nI:H - The unsupported fence write gives the attacker a GPU-initiated arbitrary-write primitive at attacker-chosen GPU virtual addresses within their VM mappings, which is memory corruption exploitable for further integrity compromise or code execution.\nA:H - Incorrect fence handling on the VCN encoder ring can hang or fault the GPU, trigger driver error-recovery paths, and cause system-wide graphics disruption or kernel oops, constituting high availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:36:30.612Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.6.141"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.12.91"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.18.33"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"7.0.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-63852","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:32:15.463568Z"}}}],"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":"2026-10-19T20:07:51.529Z"}}]}}}