CVE-2026-80736 (GCVE-0-2026-80736)
Vulnerability from cvelistv5
Published
2026-09-03 08:21
Modified
2026-09-04 04:58
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Fix bandwidth group reservation indexing
Valid bandwidth group IDs range from 1 through MAX_GROUPS, while Group
ID 0 is reserved. tb_consumed_dp_bandwidth() uses the Group ID directly
to index its local group_reserved[] array.
The array currently has MAX_GROUPS entries, so its valid indices are 0
through MAX_GROUPS - 1. Group ID MAX_GROUPS therefore accesses one
element past the end, and the final group's reserved bandwidth is not
included when the array is summed.
Give group_reserved[] MAX_GROUPS + 1 entries so direct Group ID
indexing covers the reserved ID 0 and valid IDs 1 through MAX_GROUPS.
References
| URL | Tags | |
|---|---|---|
Impacted products
{
"containers": {
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"programFiles": [
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"versionType": "git"
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"status": "affected",
"version": "52a4490e89d7c4effe613d8dffd2ac0a2a786bd7",
"versionType": "git"
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]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/thunderbolt/tb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.9"
},
{
"lessThan": "6.9",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
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"vulnerable": true
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}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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\u0027s 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": {
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}
}
},
"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"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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