{ "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" } } } }