{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1f93537881fd22712732a60ad12572a3fd40c0ec",
              "status": "affected",
              "version": "70839da6360500a82e4d5f78499284474cbed7c1",
              "versionType": "git"
            },
            {
              "lessThan": "f327e389c07cfc3a2f6ff54f6214e1a52d457edc",
              "status": "affected",
              "version": "70839da6360500a82e4d5f78499284474cbed7c1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.8",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: Fix divide-by-zero in calculate_mcache_setting on zero viewport\n\nIf a plane reaches calculate_mcache_setting with a zero-area viewport,\ncalculate_mcache_setting exits early with num_mcaches == 0 and\nmvmpg_width/height == 0. This will cause a divide-by-zero panic and can\nalso cause an underflow on num_mcaches.\n\nFix this by changing calculate_mcache_setting to bool and adding guards\nafter each calculate_mcache_row_bytes call. If num_mcaches or\nmvmpg_width/height is zero, return a false. Callers will propagate the\nfailure as a rejected mode, which prevents the panic.\n\n(cherry picked from commit 29c0f7c655f47bcbd575ff75e58480df6ec3c9da)"
        }
      ],
      "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 during DRM atomic display validation on AMDGPU DCN4.x (dml21 path): userspace ioctl \u2192 amdgpu_dm atomic commit \u2192 dc_validate_global_state/dc_validate_with_context \u2192 dcn401/dcn42_validate_bandwidth \u2192 dml2_validate \u2192 dml21_validate \u2192 dml2_check_mode_supported \u2192 dml2_core_calcs_mode_support_ex \u2192 calculate_mcache_setting; no network or physical bus is involved.\nAC:L - An attacker with DRM card access can submit atomic commits that configure DCC-enabled planes and repeatedly probe scaler/viewport edge cases (including degenerate zero-area viewports or zero mvmpg dimensions) to reach calculate_mcache_setting; once triggered, num_mcaches==0 deterministically underflows loop bounds and causes divide-by-zero without races or uncontrollable heap layout.\nPR:L - Exploitation requires only standard local DRM display privileges to perform atomic modeset ioctl on /dev/dri/card* (typical for session-owning desktop users in the video/render group), not init-namespace root/CAP_SYS_ADMIN; user namespaces do not grant independent access to the host GPU display stack.\nUI:N - No victim interaction is required beyond the attacker issuing their own DRM atomic commit to configure a plane with DCC compression enabled; the kernel panic/corruption occurs during in-kernel DML bandwidth validation, not from another user opening files or mounting filesystems.\nS:U - The vulnerability corrupts kernel memory and can enable local privilege escalation within the same host kernel running the AMDGPU display driver; it does not cross a VM, IOMMU, or sandbox boundary such as KVM guest-to-host escape.\nC:H - When num_mcaches is zero, unsigned underflow in loop bounds (n \u003c *num_mcaches_l - 1) and indexing (mcache_offsets_l[*num_mcaches_l - 1]) performs massive out-of-bounds reads/writes past the fixed-size mcache_offsets arrays in kernel DML state, enabling disclosure of adjacent kernel heap memory rather than a pure crash with no data exposure.\nI:H - The same num_mcaches underflow drives unbounded out-of-bounds writes into mode_lib mcache offset arrays and related DML structures during calculate_mcache_setting, providing attacker-influenced kernel memory corruption primitives that could be leveraged for control-flow hijacking beyond a simple denial-of-service fault.\nA:H - The vulnerable path performs integer divide-by-zero on zero mvmpg_access_width/num_mcaches and executes out-of-bounds mcache offset writes, either of which can immediately trigger a kernel oops or panic during display mode validation, denying service to all users on affected AMD DCN4.x systems until reboot."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-18T06:56:35.806Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1f93537881fd22712732a60ad12572a3fd40c0ec"
        },
        {
          "url": "https://git.kernel.org/stable/c/f327e389c07cfc3a2f6ff54f6214e1a52d457edc"
        }
      ],
      "title": "drm/amd/display: Fix divide-by-zero in calculate_mcache_setting on zero viewport",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74449",
    "datePublished": "2026-08-15T12:26:54.519Z",
    "dateReserved": "2026-08-15T05:44:03.899Z",
    "dateUpdated": "2026-08-18T06:56:35.806Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}