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VulnerabilityPublished Updated

CVE-2026-43366: Linux kernel · Race Condition

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa, c2c185be5c85d37215397c8e8781abf0a69bec1f, a7b33671e418fca507feebd1d56e7f4952a4b25c +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ c7fb19428d67dd0a2a78a4f237af01d39c78dc5a, < f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa
Fixed in
  • f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa
LinuxLinuxAffected
  • ≥ c7fb19428d67dd0a2a78a4f237af01d39c78dc5a, < c2c185be5c85d37215397c8e8781abf0a69bec1f
Fixed in
  • c2c185be5c85d37215397c8e8781abf0a69bec1f
LinuxLinuxAffected
  • ≥ c7fb19428d67dd0a2a78a4f237af01d39c78dc5a, < a7b33671e418fca507feebd1d56e7f4952a4b25c
Fixed in
  • a7b33671e418fca507feebd1d56e7f4952a4b25c
LinuxLinuxAffected
  • ≥ c7fb19428d67dd0a2a78a4f237af01d39c78dc5a, < 439a6728ec4641ffad1ca796622c19bc525e570f
Fixed in
  • 439a6728ec4641ffad1ca796622c19bc525e570f
LinuxLinuxAffected
  • ≥ c7fb19428d67dd0a2a78a4f237af01d39c78dc5a, < 97b57f69fee1b61b41acbf37e7720cac9d389fa4
Fixed in
  • 97b57f69fee1b61b41acbf37e7720cac9d389fa4
LinuxLinuxAffected
  • ≥ c7fb19428d67dd0a2a78a4f237af01d39c78dc5a, < 50ad880db3013c6fee0ef13781762a39e2e7ef83
Fixed in
  • 50ad880db3013c6fee0ef13781762a39e2e7ef83

AI-suggested

A fix for this vulnerability is available and has been applied in specific Linux kernel commits. Users and administrators should update affected Linux kernel versions to the patched releases containing these fixes. Since this is a kernel-level issue, applying the official patches or upgrading to a fixed kernel version is the recommended mitigation.

Description

CVE-2026-43366 is a high-severity vulnerability in the Linux kernel's io_uring subsystem affecting version 5.19. It involves improper checks during buffer recycling where a legacy buffer list may be incorrectly handled if it has been upgraded to a ring-provided type. This flaw could lead to critical impacts on confidentiality, integrity, and availability.

References

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