What is CVE-2026-43366?

CVE-2026-43366 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, affecting Linux kernel versions from 5.19 onward and patched in 6.1.167, 6.6.130, 6.12.78 and others. CVE-2026-43366 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43366?

CVE-2026-43366 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-43366?

Yes, CVE-2026-43366 has been patched. Fixed versions include 6.1.167, 6.6.130, 6.12.78 and others. If you are running Linux kernel 5.19 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43366 actively exploited?

CVE-2026-43366 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-43366

High

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.

Package Linux Kernel

Published 2026-05-08

Last modified 2026-05-15

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 5.19 and later are affected. Fixed in 6.1.167, 6.6.130, 6.12.78, 6.18.19, 6.19.9, 7.0 and their respective stable series.

Affected from

≥ 5.19

Fixed in

✓ 6.1.167 6.1.x ✓ 6.6.130 6.6.x ✓ 6.12.78 6.12.x ✓ 6.18.19 6.18.x ✓ 6.19.9 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43366 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/439a6728ec4641ffad1ca796622c19bc525e570f
Patch
Kernel patch commit
https://git.kernel.org/stable/c/50ad880db3013c6fee0ef13781762a39e2e7ef83
Patch
Kernel patch commit
https://git.kernel.org/stable/c/97b57f69fee1b61b41acbf37e7720cac9d389fa4
Patch

6 patch commits total View all on NVD

Details

CVE ID CVE-2026-43366

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2026-05-08

Modified 2026-05-15

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43366?

CVE-2026-43366 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 5.19 onward and has been patched in 6.1.167, 6.6.130, 6.12.78 and others. CVE-2026-43366 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43366?

CVE-2026-43366 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-43366?

Yes — CVE-2026-43366 has been patched. Fixed versions include 6.1.167, 6.6.130, 6.12.78 and others. If you are running Linux kernel 5.19 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43366 actively exploited?

No — CVE-2026-43366 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.