{"api_version":"1","generated_at":"2026-09-14T08:03:53+00:00","cve":"CVE-2026-80736","urls":{"html":"https://cve.report/CVE-2026-80736","api":"https://cve.report/api/cve/CVE-2026-80736.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80736","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80736"},"summary":{"title":"thunderbolt: Fix bandwidth group reservation indexing","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: Fix bandwidth group reservation indexing\n\nValid bandwidth group IDs range from 1 through MAX_GROUPS, while Group\nID 0 is reserved. tb_consumed_dp_bandwidth() uses the Group ID directly\nto index its local group_reserved[] array.\n\nThe array currently has MAX_GROUPS entries, so its valid indices are 0\nthrough MAX_GROUPS - 1. Group ID MAX_GROUPS therefore accesses one\nelement past the end, and the final group's reserved bandwidth is not\nincluded when the array is summed.\n\nGive group_reserved[] MAX_GROUPS + 1 entries so direct Group ID\nindexing covers the reserved ID 0 and valid IDs 1 through MAX_GROUPS.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-03 13:06:12","updated_at":"2026-09-04 05:17:14"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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"}}],"references":[{"url":"https://git.kernel.org/stable/c/0bfb67ba366cd68d1d0ad935760577bae1d5df27","name":"https://git.kernel.org/stable/c/0bfb67ba366cd68d1d0ad935760577bae1d5df27","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d2ee4d47aacbd2ba456092eeec670dba35fde291","name":"https://git.kernel.org/stable/c/d2ee4d47aacbd2ba456092eeec670dba35fde291","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0a8c9ed4f166216642a8c084f0de415169c88088","name":"https://git.kernel.org/stable/c/0a8c9ed4f166216642a8c084f0de415169c88088","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9977321835c7ae71d12a43bed7baa5bd514d01c3","name":"https://git.kernel.org/stable/c/9977321835c7ae71d12a43bed7baa5bd514d01c3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80736","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80736","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 52a4490e89d7c4effe613d8dffd2ac0a2a786bd7 0bfb67ba366cd68d1d0ad935760577bae1d5df27 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 52a4490e89d7c4effe613d8dffd2ac0a2a786bd7 9977321835c7ae71d12a43bed7baa5bd514d01c3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 52a4490e89d7c4effe613d8dffd2ac0a2a786bd7 0a8c9ed4f166216642a8c084f0de415169c88088 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 52a4490e89d7c4effe613d8dffd2ac0a2a786bd7 d2ee4d47aacbd2ba456092eeec670dba35fde291 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: Fix bandwidth group reservation indexing\n\nValid bandwidth group IDs range from 1 through MAX_GROUPS, while Group\nID 0 is reserved. tb_consumed_dp_bandwidth() uses the Group ID directly\nto index its local group_reserved[] array.\n\nThe array currently has MAX_GROUPS entries, so its valid indices are 0\nthrough MAX_GROUPS - 1. Group ID MAX_GROUPS therefore accesses one\nelement past the end, and the final group's reserved bandwidth is not\nincluded when the array is summed.\n\nGive group_reserved[] MAX_GROUPS + 1 entries so direct Group ID\nindexing covers the reserved ID 0 and valid IDs 1 through MAX_GROUPS."}],"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 flaw is reached through the local Thunderbolt connection manager control channel (TB_CFG_ERROR_DP_BW notifications into tb_handle_dp_bandwidth_request/tb_alloc_dp_bandwidth), not over IP; on systems with authorized TB docks/workstations, DP bandwidth recalculation can be driven without new network access.\nAC:L - After an authorized topology uses bandwidth group 7 with reserved DP bandwidth, the out-of-bounds write at group_reserved[7] is deterministic whenever tb_consumed_dp_bandwidth() runs; an attacker can induce the needed bandwidth reductions/mode changes rather than depending on uncontrollable timing.\nPR:L - The vulnerable path performs no credential checks; once Thunderbolt devices are authorized (common with security level none or boot ACL), an unprivileged local user can trigger DP bandwidth allocation events via display/mode changes that cause DPTX bandwidth notifications.\nUI:N - No victim interaction is required beyond normal authorized Thunderbolt/DisplayPort operation; a local attacker can directly cause the bandwidth-change notifications that reach tb_consumed_dp_bandwidth() without convincing another user to perform a separate action.\nS:U - Impact is kernel stack corruption during Thunderbolt bandwidth accounting in the host kernel; it does not cross a VM/host, IOMMU/DMA, or sandbox security boundary and stays within the same kernel security authority.\nC:H - Indexing group_reserved[] with group ID 7 writes one 32-bit word past a seven-element stack array, corrupting adjacent stack data with attacker-influenced reserved-bandwidth values and enabling kernel memory disclosure primitives.\nI:H - This is a kernel stack out-of-bounds write with partially attacker-controlled values (reserved Mb/s), which can corrupt pointers/control data on the stack and be leveraged for arbitrary kernel memory modification or privilege escalation.\nA:H - Corrupting kernel stack variables in tb_consumed_dp_bandwidth() can cause immediate kernel oops/panic or hang during bandwidth accounting, and unstable stack corruption commonly produces severe system unavailability."}]}],"providerMetadata":{"dateUpdated":"2026-09-04T04:58:21.747Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/0bfb67ba366cd68d1d0ad935760577bae1d5df27"},{"url":"https://git.kernel.org/stable/c/9977321835c7ae71d12a43bed7baa5bd514d01c3"},{"url":"https://git.kernel.org/stable/c/0a8c9ed4f166216642a8c084f0de415169c88088"},{"url":"https://git.kernel.org/stable/c/d2ee4d47aacbd2ba456092eeec670dba35fde291"}],"title":"thunderbolt: Fix bandwidth group reservation indexing","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80736","datePublished":"2026-09-03T08:21:51.946Z","dateReserved":"2026-08-26T14:34:25.789Z","dateUpdated":"2026-09-04T04:58:21.747Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-03 13:06:12","lastModifiedDate":"2026-09-04 05:17:14","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80736","Ordinal":"1","Title":"thunderbolt: Fix bandwidth group reservation indexing","CVE":"CVE-2026-80736","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80736","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: Fix bandwidth group reservation indexing\n\nValid bandwidth group IDs range from 1 through MAX_GROUPS, while Group\nID 0 is reserved. tb_consumed_dp_bandwidth() uses the Group ID directly\nto index its local group_reserved[] array.\n\nThe array currently has MAX_GROUPS entries, so its valid indices are 0\nthrough MAX_GROUPS - 1. Group ID MAX_GROUPS therefore accesses one\nelement past the end, and the final group's reserved bandwidth is not\nincluded when the array is summed.\n\nGive group_reserved[] MAX_GROUPS + 1 entries so direct Group ID\nindexing covers the reserved ID 0 and valid IDs 1 through MAX_GROUPS.","Type":"Description","Title":"thunderbolt: Fix bandwidth group reservation indexing"}]}}}