{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63852","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.016Z","datePublished":"2026-07-19T14:04:43.258Z","dateUpdated":"2026-08-05T12:36:30.612Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:36:30.612Z"},"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)"}],"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."}]}],"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_3.c"],"versions":[{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","lessThan":"c12a5d35033c0640c57c10d7111c010c7b9c2c8e","status":"affected","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","lessThan":"387b7c7667bd5c53549350ddad866d2fcf75a529","status":"affected","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","lessThan":"9076a83e5adefd10dc5c967c7b8bde601c4c512a","status":"affected","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","lessThan":"0177ac6141c8857130cf365369c74dee7b6b1f7f","status":"affected","versionType":"git"},{"version":"b889ef4ac98837838c38f7b9f72bba2f33ee367d","lessThan":"4532b52b34e4e4310386e6fdf6a643368599f522","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_3.c"],"versions":[{"version":"6.5","status":"affected"},{"version":"0","lessThan":"6.5","status":"unaffected","versionType":"semver"},{"version":"6.6.141","lessThanOrEqual":"6.6.*","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":"6.5","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"}]}]}],"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"}],"title":"drm/amdgpu/vcn: set no_user_fence for VCN v4.0.3 enc ring","x_generator":{"engine":"bippy-1.2.0"}}}}