FKIE_CVE-2026-89747
Vulnerability from fkie_nvd - Published: 2026-09-11 20:20 - Updated: 2026-09-13 07:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
Writing to buffer_subbuf_size_kb calls ring_buffer_subbuf_order_set(),
which frees every sub-buffer of the ring buffer, including the reader
page, and replaces them with newly allocated ones.
Readers of trace_pipe hold pointers into those pages. ring_buffer_peek()
looks up an event under cpu_buffer->reader_lock but returns the event
pointer after dropping the lock, and peek_next_entry() then calls
ring_buffer_event_length() and ring_buffer_event_data() on it. If the
sub-buffer order is changed in that window, the reader dereferences
freed memory:
BUG: KASAN: use-after-free in ring_buffer_peek+0x3e0/0x430
Read of size 1 at addr ffff88802a4cf010 by task syz-executor989/6002
Freed by:
free_buffer_page kernel/trace/ring_buffer.c:398 [inline]
ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444
buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221
Take trace_access_lock(RING_BUFFER_ALL_CPUS) around the order change.
This is the lock trace_pipe readers already hold across their entire
peek-and-print loop, so the swap can no longer race with a reader that
is dereferencing a peeked event.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/trace/trace.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "05ebe1e1d7d38c2612bacfefe043a33572ae34cb",
"status": "affected",
"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
"versionType": "git"
},
{
"lessThan": "ddbe921ed16a0ad2d9e09574c3f3aabec7528325",
"status": "affected",
"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
"versionType": "git"
},
{
"lessThan": "7a49d19ff9baaf61217e5ec14199c18bc2d93ee4",
"status": "affected",
"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
"versionType": "git"
},
{
"lessThan": "372f8534244d632ad5118e8a87a11291b01712d3",
"status": "affected",
"version": "f9b94daa542a8d2532f0930f01cd9aec2d19621b",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/trace/trace.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.8"
},
{
"lessThan": "6.8",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free in trace_pipe read on sub-buffer order change\n\nWriting to buffer_subbuf_size_kb calls ring_buffer_subbuf_order_set(),\nwhich frees every sub-buffer of the ring buffer, including the reader\npage, and replaces them with newly allocated ones.\n\nReaders of trace_pipe hold pointers into those pages. ring_buffer_peek()\nlooks up an event under cpu_buffer-\u003ereader_lock but returns the event\npointer after dropping the lock, and peek_next_entry() then calls\nring_buffer_event_length() and ring_buffer_event_data() on it. If the\nsub-buffer order is changed in that window, the reader dereferences\nfreed memory:\n\n BUG: KASAN: use-after-free in ring_buffer_peek+0x3e0/0x430\n Read of size 1 at addr ffff88802a4cf010 by task syz-executor989/6002\n\n Freed by:\n free_buffer_page kernel/trace/ring_buffer.c:398 [inline]\n ring_buffer_subbuf_order_set+0x1325/0x18e0 kernel/trace/ring_buffer.c:7444\n buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:8221\n\nTake trace_access_lock(RING_BUFFER_ALL_CPUS) around the order change.\nThis is the lock trace_pipe readers already hold across their entire\npeek-and-print loop, so the swap can no longer race with a reader that\nis dereferencing a peeked event."
}
],
"id": "CVE-2026-89747",
"lastModified": "2026-09-13T07:17:39.363",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-09-11T20:20:05.517",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/05ebe1e1d7d38c2612bacfefe043a33572ae34cb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/372f8534244d632ad5118e8a87a11291b01712d3"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7a49d19ff9baaf61217e5ec14199c18bc2d93ee4"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ddbe921ed16a0ad2d9e09574c3f3aabec7528325"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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