CVE-2026-43366

Local privilege escalation via buffer-list type race

Published May 8, 2026 · Updated May 8, 2026

Race condition in Linux Kernel starting in 5.19 allows local users to gain kernel privileges through io_uring legacy buffer recycling. In io_uring/kbuf.c, legacy recycling reuses a saved buffer without verifying that its target list still exists and remains a legacy list. Low-privileged local access and an io-wq-forced request are required; racing a list upgrade corrupts kernel state, permitting escalation or a kernel crash.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux Kernel starting in 5.19 allows local users to gain kernel privileges through io_uring legacy buffer recycling. In io_uring/kbuf.c, legacy recycling reuses a saved buffer without verifying that its target list still exists and remains a legacy list. Low-privileged local access and an io-wq-forced request are required; racing a list upgrade corrupts kernel state, permitting escalation or a kernel crash.

The record

CVE
CVE-2026-43366
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.19
  2. Affected versionversion=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <439a6728ec4641ffad1ca796622c19bc525e570f
  3. Affected versionversion=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <50ad880db3013c6fee0ef13781762a39e2e7ef83
  4. Affected versionversion=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <97b57f69fee1b61b41acbf37e7720cac9d389fa4
  5. Affected versionversion=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <a7b33671e418fca507feebd1d56e7f4952a4b25c
  6. Affected versionversion=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <c2c185be5c85d37215397c8e8781abf0a69bec1f
  7. Affected versionversion=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.19; version=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <439a6728ec4641ffad1ca796622c19bc525e570f; version=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <50ad880db3013c6fee0ef13781762a39e2e7ef83; version=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <97b57f69fee1b61b41acbf37e7720cac9d389fa4; version=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <a7b33671e418fca507feebd1d56e7f4952a4b25c; version=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <c2c185be5c85d37215397c8e8781abf0a69bec1f; version=c7fb19428d67dd0a2a78a4f237af01d39c78dc5a <f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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