FKIE_CVE-2026-74601
Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Use current_context for safe per-CPU buffer swap
The ring_buffer_swap_cpu() function currently checks the per-CPU
committing counter to determine if a buffer is actively being written to
before performing the swap. However, there exists a race window where
this check can be bypassed:
ring_buffer_lock_reserve
cpu_buffer = buffer->buffers[cpu]; // cpu_buffer_a
rb_reserve_next_event
rb_start_commit // inc committing
if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
__rb_reserve_next
rb_move_tail
rb_end_commit(cpu_buffer); // dec committing => 0
/* interrupt hits here, successfully swaps! */
local_inc(&cpu_buffer->committing);
ring_buffer_unlock_commit
cpu_buffer = buffer->buffers[cpu]; // cpu_buffer_b
rb_commit
rb_end_commit
RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
// triggers warning
The committing counter can temporarily drop to 0 during a single write
operation (within rb_move_tail), creating a window where swap can
succeed even though the write is still in progress. This leads to
inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().
Replace the committing counter check with current_context checks, which
are set at the entry of ring_buffer_lock_reserve() and remain valid
throughout the entire write operation, providing a reliable indicator of
buffer busy state during swap.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/trace/ring_buffer.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "26662bc8fced1d668fa1aa146eda085bfc67bd0b",
"status": "affected",
"version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
"versionType": "git"
},
{
"lessThan": "6b524e6b234e45c7f5f90d13b042c6f57f80105c",
"status": "affected",
"version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
"versionType": "git"
},
{
"lessThan": "597f279b7b4a06412e3d965e98cc36e181cdbede",
"status": "affected",
"version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
"versionType": "git"
},
{
"lessThan": "22709117d9ae95e52673685f98caac7c356a8227",
"status": "affected",
"version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
"versionType": "git"
},
{
"lessThan": "ad7e10c7ea89af45ac1bf1814855d45da472703d",
"status": "affected",
"version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
"versionType": "git"
},
{
"lessThan": "5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f",
"status": "affected",
"version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
"versionType": "git"
},
{
"lessThan": "5e6e2a18c20e88167d414f666032792e8bf19b80",
"status": "affected",
"version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
"versionType": "git"
},
{
"lessThan": "f27bdc43077e4fcb5557dfc315ee8d91e741f483",
"status": "affected",
"version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/trace/ring_buffer.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.5"
},
{
"lessThan": "4.5",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.266",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.217",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.105",
"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"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Use current_context for safe per-CPU buffer swap\n\nThe ring_buffer_swap_cpu() function currently checks the per-CPU\ncommitting counter to determine if a buffer is actively being written to\nbefore performing the swap. However, there exists a race window where\nthis check can be bypassed:\n\n ring_buffer_lock_reserve\n cpu_buffer = buffer-\u003ebuffers[cpu]; // cpu_buffer_a\n rb_reserve_next_event\n rb_start_commit // inc committing\n if (unlikely(READ_ONCE(cpu_buffer-\u003ebuffer) != buffer)) {...}\n __rb_reserve_next\n rb_move_tail\n rb_end_commit(cpu_buffer); // dec committing =\u003e 0\n /* interrupt hits here, successfully swaps! */\n local_inc(\u0026cpu_buffer-\u003ecommitting);\n\n ring_buffer_unlock_commit\n cpu_buffer = buffer-\u003ebuffers[cpu]; // cpu_buffer_b\n rb_commit\n rb_end_commit\n RB_WARN_ON(cpu_buffer, !local_read(\u0026cpu_buffer-\u003ecommitting))\n // triggers warning\n\nThe committing counter can temporarily drop to 0 during a single write\noperation (within rb_move_tail), creating a window where swap can\nsucceed even though the write is still in progress. This leads to\ninconsistent buffer state and triggers the RB_WARN_ON in rb_commit().\n\nReplace the committing counter check with current_context checks, which\nare set at the entry of ring_buffer_lock_reserve() and remain valid\nthroughout the entire write operation, providing a reliable indicator of\nbuffer busy state during swap."
}
],
"id": "CVE-2026-74601",
"lastModified": "2026-08-25T06:18:36.057",
"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": "2026-08-22T16:16:32.530",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/22709117d9ae95e52673685f98caac7c356a8227"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/26662bc8fced1d668fa1aa146eda085bfc67bd0b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/597f279b7b4a06412e3d965e98cc36e181cdbede"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/5e6e2a18c20e88167d414f666032792e8bf19b80"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6b524e6b234e45c7f5f90d13b042c6f57f80105c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ad7e10c7ea89af45ac1bf1814855d45da472703d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f27bdc43077e4fcb5557dfc315ee8d91e741f483"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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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.
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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