{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74449", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.899Z", "datePublished": "2026-08-15T12:26:54.519Z", "dateUpdated": "2026-10-21T12:45:40.556Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:45:40.556Z"}, "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": {"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 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 < *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."}]}], "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/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c"], "versions": [{"version": "70839da6360500a82e4d5f78499284474cbed7c1", "lessThan": "70f5f4ddba0d2d89e77ec13b79cdcfbef33be0d9", "status": "affected", "versionType": "git"}, {"version": "70839da6360500a82e4d5f78499284474cbed7c1", "lessThan": "23a541c31b45fa813b33269376f6bd53535429a8", "status": "affected", "versionType": "git"}, {"version": "70839da6360500a82e4d5f78499284474cbed7c1", "lessThan": "1f93537881fd22712732a60ad12572a3fd40c0ec", "status": "affected", "versionType": "git"}, {"version": "70839da6360500a82e4d5f78499284474cbed7c1", "lessThan": "f327e389c07cfc3a2f6ff54f6214e1a52d457edc", "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/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn4_calcs.c"], "versions": [{"version": "6.11", "status": "affected"}, {"version": "0", "lessThan": "6.11", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.8", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "6.11", "versionEndExcluding": "6.12.114"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.18.57"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.1.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/70f5f4ddba0d2d89e77ec13b79cdcfbef33be0d9"}, {"url": "https://git.kernel.org/stable/c/23a541c31b45fa813b33269376f6bd53535429a8"}, {"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"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-74449", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T18:56:48.300764Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:05:46.407Z"}}]}}