CVE-2026-89819 (GCVE-0-2026-89819)
Vulnerability from cvelistv5
Published
2026-09-16 10:30
Modified
2026-10-19 08:53
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: validate plane degamma LUT size for private color prop Unlike the CRTC degamma path, which is guarded by amdgpu_dm_verify_lut_sizes(), the per-plane degamma LUT size was never validated before use. __set_dm_plane_degamma() passed the user-supplied size straight into __is_lut_linear() and, for a non-linear LUT, into __set_input_tf() -> __drm_lut_to_dc_gamma(), the latter always iterating MAX_COLOR_LUT_ENTRIES entries regardless of the actual LUT size. A malformed AMD_PLANE_DEGAMMA_LUT blob (e.g. a single entry) could thus trigger a divide-by-zero in __is_lut_linear() or an out-of-bounds read in __drm_lut_to_dc_gamma(). Reject any plane degamma LUT whose size does not match MAX_COLOR_LUT_ENTRIES, mirroring the invariant the code already asserts a few lines below (and which the CRTC path enforces). The AMD_PLANE_DEGAMMA_LUT property is only exposed on builds with AMD_PRIVATE_COLOR defined.
References
Impacted products
Vendor Product Version
Linux Linux Version: 980f8710075acaeb226a94cde6dda8ffad30123c
Version: 980f8710075acaeb226a94cde6dda8ffad30123c
Version: 980f8710075acaeb226a94cde6dda8ffad30123c
Version: 980f8710075acaeb226a94cde6dda8ffad30123c
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "status": "affected",
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        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "version": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: validate plane degamma LUT size for private color prop\n\nUnlike the CRTC degamma path, which is guarded by\namdgpu_dm_verify_lut_sizes(), the per-plane degamma LUT size was never\nvalidated before use. __set_dm_plane_degamma() passed the user-supplied\nsize straight into __is_lut_linear() and, for a non-linear LUT, into\n__set_input_tf() -\u003e __drm_lut_to_dc_gamma(), the latter always iterating\nMAX_COLOR_LUT_ENTRIES entries regardless of the actual LUT size.\n\nA malformed AMD_PLANE_DEGAMMA_LUT blob (e.g. a single entry) could thus\ntrigger a divide-by-zero in __is_lut_linear() or an out-of-bounds read in\n__drm_lut_to_dc_gamma(). Reject any plane degamma LUT whose size does not\nmatch MAX_COLOR_LUT_ENTRIES, mirroring the invariant the code already\nasserts a few lines below (and which the CRTC path enforces).\n\nThe AMD_PLANE_DEGAMMA_LUT property is only exposed on builds with\nAMD_PRIVATE_COLOR defined."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only through local DRM ioctls (DRM_IOCTL_MODE_CREATEPROPBLOB then DRM_IOCTL_MODE_ATOMIC or MODE_OBJ_SETPROPERTY) on /dev/dri/cardN when setting AMD_PLANE_DEGAMMA_LUT, a private plane property on AMDGPU display; no network or remote-peer path exists into amdgpu_dm color management.\nAC:L - The attacker fully controls the LUT blob size and contents and can deterministically trigger a divide-by-zero with a one-entry blob or a large heap over-read with a short non-linear LUT; no race, memory-layout luck, or victim state is required.\nPR:L - DRM_IOCTL_MODE_ATOMIC requires DRM master, which is the normal state of the logged-in graphical-session user (compositor, gamescope, kiosk, Steam Deck, Android) or the first opener of an unclaimed card; no CAP_SYS_ADMIN or real root is needed.\nUI:N - The attacker creates the undersized blob and issues the atomic commit from their own process; no other user must open a file, plug in a display, or take any action.\nS:U - The divide-by-zero and out-of-bounds read occur in kernel context on the same host inside the amdgpu display driver; impact stays within the kernel security authority with no VM, IOMMU, or sandbox boundary crossed.\nC:H - __drm_lut_to_dc_gamma() always walks MAX_COLOR_LUT_ENTRIES (4096) drm_color_lut records regardless of blob length, over-reading about 32KB of adjacent kernel heap from a short LUT blob and copying those values into dc_gamma and the display pipeline.\nI:H - Kernel heap contents from the over-read are stored into dc_gamma entries and applied by apply_lut_1d() into the plane transfer function that is programmed into DPP degamma hardware, corrupting driver and GPU color-management state with unvalidated memory.\nA:H - A one-entry LUT causes a divide-error (#DE) panic in __is_lut_linear(); a short non-linear LUT makes __drm_lut_to_dc_gamma() walk tens of kilobytes past the blob into potentially unmapped heap, oopsing the kernel on the atomic check/commit path."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:53:13.333Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f6f04d8ae5725bcc893bdc62e3467efd97255c5b"
        },
        {
          "url": "https://git.kernel.org/stable/c/0b2615b8b54f58bbdf986dffb38cbc35214a5cc5"
        },
        {
          "url": "https://git.kernel.org/stable/c/b10cc09b329245c6d95f8fa3e7f068575e3e0e9f"
        },
        {
          "url": "https://git.kernel.org/stable/c/e4c3ab59021e7c146a84b6671f0d530972bd58b4"
        }
      ],
      "title": "drm/amd/display: validate plane degamma LUT size for private color prop",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89819",
    "datePublished": "2026-09-16T10:30:51.898Z",
    "dateReserved": "2026-09-11T19:38:34.768Z",
    "dateUpdated": "2026-10-19T08:53:13.333Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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