CVE-2026-43366 (GCVE-0-2026-43366)
Vulnerability from cvelistv5 – Published: 2026-05-08 14:21 – Updated: 2026-08-05 12:27
VLAI
EPSS
VEX
Title
io_uring/kbuf: check if target buffer list is still legacy on recycle
Summary
In the Linux kernel, the following vulnerability has been resolved:
io_uring/kbuf: check if target buffer list is still legacy on recycle
There's a gap between when the buffer was grabbed and when it
potentially gets recycled, where if the list is empty, someone could've
upgraded it to a ring provided type. This can happen if the request
is forced via io-wq. The legacy recycling is missing checking if the
buffer_list still exists, and if it's of the correct type. Add those
checks.
Severity
7.8 (High)
Assigner
References
6 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < a7b33671e418fca507feebd1d56e7f4952a4b25c
(git)
Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < 439a6728ec4641ffad1ca796622c19bc525e570f (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < 50ad880db3013c6fee0ef13781762a39e2e7ef83 (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < 97b57f69fee1b61b41acbf37e7720cac9d389fa4 (git) Affected: c7fb19428d67dd0a2a78a4f237af01d39c78dc5a , < c2c185be5c85d37215397c8e8781abf0a69bec1f (git) |
guessed | |
| Linux | Linux |
Affected:
5.19
Unaffected: 0 , < 5.19 (semver) Unaffected: 6.1.167 , ≤ 6.1.* (semver) Unaffected: 6.6.130 , ≤ 6.6.* (semver) Unaffected: 6.12.78 , ≤ 6.12.* (semver) Unaffected: 6.18.19 , ≤ 6.18.* (semver) Unaffected: 6.19.9 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
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"programFiles": [
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},
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},
{
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"version": "6.18.19",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.19.9",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
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{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: check if target buffer list is still legacy on recycle\n\nThere\u0027s a gap between when the buffer was grabbed and when it\npotentially gets recycled, where if the list is empty, someone could\u0027ve\nupgraded it to a ring provided type. This can happen if the request\nis forced via io-wq. The legacy recycling is missing checking if the\nbuffer_list still exists, and if it\u0027s of the correct type. Add those\nchecks."
}
],
"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 code is reachable through local `io_uring_setup`, `io_uring_enter`, and `io_uring_register` operations using provided buffer selection and buffer-ring registration. It is not directly reachable from network packets or physical/adjacent interfaces.\nAC:L - The attacker controls the io_uring ring, the legacy provided buffer group, the in-flight async/io-wq request, and the conversion/removal of the same buffer group. The required timing can be driven by attacker-controlled concurrent local operations, so the race/lifecycle window is low complexity.\nPR:L - Exploitation requires a local unprivileged user able to create and use an io_uring instance; the relevant setup/register/submit paths do not require real root or init-namespace capabilities when io_uring is enabled. This is basic local user privilege, not administrator privilege.\nUI:N - No victim action is required after the attacker runs local code. The attacker performs all setup, submission, and buffer group conversion operations directly.\nS:U - The bug corrupts kernel memory from within the kernel/io_uring security authority and can lead to local kernel compromise or crash. It does not inherently cross a VM, IOMMU, or separate authorization boundary.\nC:H - The legacy recycle path can type-confuse a ring-provided buffer list and write kernel pointers into attacker-observable ring memory, and subsequent use can treat attacker-influenced objects as buffer-ring state. This is kernel memory corruption with a defensible path to high confidentiality impact.\nI:H - Recycling a legacy `struct io_buffer` into a ring buffer list corrupts list/ring state and can turn later ring-buffer operations into controlled kernel memory misuse. As a type confusion/memory corruption bug, high integrity impact is appropriate.\nA:H - If the target buffer list has been removed the old code can dereference a NULL buffer-list pointer, and if it has been upgraded it corrupts kernel state. Either case can produce an oops/panic or otherwise destabilize the kernel."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-05T12:27:30.302Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"url": "https://git.kernel.org/stable/c/439a6728ec4641ffad1ca796622c19bc525e570f"
},
{
"url": "https://git.kernel.org/stable/c/f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa"
},
{
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},
{
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},
{
"url": "https://git.kernel.org/stable/c/c2c185be5c85d37215397c8e8781abf0a69bec1f"
}
],
"title": "io_uring/kbuf: check if target buffer list is still legacy on recycle",
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"cveId": "CVE-2026-43366",
"datePublished": "2026-05-08T14:21:19.191Z",
"dateReserved": "2026-05-01T14:12:56.005Z",
"dateUpdated": "2026-08-05T12:27:30.302Z",
"state": "PUBLISHED"
},
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"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-43366",
"date": "2026-09-15",
"epss": "0.0013",
"percentile": "0.02957"
},
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Add 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"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-07-02T12:46:36+00:00",
"cve": "CVE-2026-43366",
"id": "CVE-2026-43366",
"initial_release_date": "2026-05-08T00:00:00+00:00",
"product_status:known_affected": "184",
"product_status:known_not_affected": "90",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: io_uring/kbuf: check if target buffer list is still legacy on recycle",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43366.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "important",
"current_release_date": "2026-09-11T01:18:12Z",
"cve": "CVE-2026-43366",
"id": "CVE-2026-43366",
"initial_release_date": "2026-05-13T03:34:50Z",
"product_status:first_fixed": "2",
"product_status:known_affected": "394",
"product_status:known_not_affected": "221",
"product_status:recommended": "540",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2026-43366",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-43366.json",
"version": "35"
}
}
}
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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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