CVE-2026-64402 (GCVE-0-2026-64402)
Vulnerability from cvelistv5
Published
2026-07-25 08:50
Modified
2026-08-17 04:55
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()
When the SMB sink is used as a perf AUX sink, smb_update_buffer() calls
smb_sync_perf_buffer() to copy hardware trace data into the perf AUX ring
buffer pages. It derives pg_idx = head >> PAGE_SHIFT from @head, which is
handle->head, and indexes dst_pages[pg_idx]. The pg_idx %= nr_pages
normalization is only applied after the first loop iteration.
This leaves the initial page index underived from the buffer size, which
can result in an out-of-bounds write past dst_pages[] when head exceeds
the AUX buffer size.
Normalize head modulo the AUX buffer size before deriving the page index
and offset, mirroring tmc_etr_sync_perf_buffer().
References
Impacted products
{
"containers": {
"cna": {
"affected": [
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"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/hwtracing/coresight/ultrasoc-smb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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},
{
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"product": "Linux",
"programFiles": [
"drivers/hwtracing/coresight/ultrasoc-smb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.3"
},
{
"lessThan": "6.3",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.96",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
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"vulnerable": true
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}
],
"negate": false,
"operator": "OR"
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}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncoresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()\n\nWhen the SMB sink is used as a perf AUX sink, smb_update_buffer() calls\nsmb_sync_perf_buffer() to copy hardware trace data into the perf AUX ring\nbuffer pages. It derives pg_idx = head \u003e\u003e PAGE_SHIFT from @head, which is\nhandle-\u003ehead, and indexes dst_pages[pg_idx]. The pg_idx %= nr_pages\nnormalization is only applied after the first loop iteration.\n\nThis leaves the initial page index underived from the buffer size, which\ncan result in an out-of-bounds write past dst_pages[] when head exceeds\nthe AUX buffer size.\n\nNormalize head modulo the AUX buffer size before deriving the page index\nand offset, mirroring tmc_etr_sync_perf_buffer()."
}
],
"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 vulnerable path is reached locally through perf_event_open(), AUX-buffer mmap, and perf event scheduling or ioctls; it has no network or physical entry point.\nAC:L - An attacker can choose a small AUX buffer, advance aux_tail, and repeatedly stop and restart their own trace until the monotonically increasing head crosses the buffer size. No race or condition outside the attacker\u0027s control is required.\nPR:L - A self-targeted event with exclude_kernel=1 is available to an ordinary unprivileged user under the mainline default perf_event_paranoid setting, and selecting the SMB sink requires no privileged sysfs write.\nUI:N - The attacker creates, runs, consumes, and stops their own tracing event without any victim action.\nS:U - Exploitation compromises the host kernel within the same security authority and does not inherently cross a VM, IOMMU, or other separate security boundary.\nC:H - The out-of-range page-pointer lookup directs memcpy() through a pointer obtained from groomable adjacent kernel memory. Resulting kernel-memory corruption can plausibly enable control-flow hijacking and unrestricted disclosure.\nI:H - The attacker-influenced trace data is written through an invalid kernel pointer, providing exploitable memory corruption that can plausibly yield arbitrary kernel modification or code execution.\nA:H - An ungroomed invalid destination pointer can immediately cause a kernel oops or panic, and the attacker can trigger the path repeatedly."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:55:00.113Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/38dbc8db8341ccdf8e1e1a067453d33ad751864b"
},
{
"url": "https://git.kernel.org/stable/c/4c5a0a946373da99a80398289b28845b5ae40cd1"
},
{
"url": "https://git.kernel.org/stable/c/661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb"
},
{
"url": "https://git.kernel.org/stable/c/daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f"
},
{
"url": "https://git.kernel.org/stable/c/98495b5a4d77dd22e106f462b76e1093a55b29a7"
}
],
"title": "coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64402",
"datePublished": "2026-07-25T08:50:45.075Z",
"dateReserved": "2026-07-19T15:36:31.785Z",
"dateUpdated": "2026-08-17T04:55:00.113Z",
"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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