What is CVE-2026-43253?

CVE-2026-43253 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10, classified as a Improper Locking flaw (CWE-667), affecting Linux kernel versions from 4.9 onward and patched in 6.6.128, 6.12.75, 6.18.16 and others. CVE-2026-43253 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43253?

CVE-2026-43253 has a CVSS score of 7.5 out of 10, rated High severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-43253?

Yes, CVE-2026-43253 has been patched. Fixed versions include 6.6.128, 6.12.75, 6.18.16 and others. If you are running Linux kernel 4.9 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43253 actively exploited?

CVE-2026-43253 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Improper Locking (CWE-667)?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/667.html

CVE-2026-43253

High

In the Linux kernel, the following vulnerability has been resolved: iommu/amd: move wait_on_sem() out of spinlock With iommu.strict=1, the existing completion wait path can cause soft lockups under stressed environment, as wait_on_sem() busy-waits under the spinlock with interrupts disabled. Move the completion wait in iommu_completion_wait() out of the spinlock. wait_on_sem() only polls the hardware-updated cmd_sem and does not require iommu->lock, so holding the lock during the busy wait unnecessarily increases contention and extends the time with interrupts disabled.

Package Linux Kernel

Published 2026-05-06

Last modified 2026-05-11

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.5

out of 10

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-667

CVE-2026-43253 is a Improper Locking vulnerability

What is Improper Locking?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. Learn more on MITRE CWE

Affected versions

Linux kernel versions 4.9 and later are affected. Fixed in 6.6.128, 6.12.75, 6.18.16, 6.19.6, 7.0 and their respective stable series.

Affected from

≥ 4.9

Fixed in

✓ 6.6.128 6.6.x ✓ 6.12.75 6.12.x ✓ 6.18.16 6.18.x ✓ 6.19.6 6.19.x ✓ 7.0

References

5 total

Kernel Git
https://git.kernel.org/stable/c/496269d12072ecb219826485bdbec70c92a8eef5

Patch
Kernel Git
https://git.kernel.org/stable/c/715c263119fd1b918a9fcbd8a36ea5b604a46324

Patch
Kernel Git
https://git.kernel.org/stable/c/d2a0cac10597068567d336e85fa3cbdbe8ca62bf

Patch
Kernel Git
https://git.kernel.org/stable/c/e15768e68820142077bbca402d8e902f64ade1b0

Patch
Kernel Git
https://git.kernel.org/stable/c/f2f65b28d802a667119147444ec2ae33eebf9a58

Patch

Details

CVE ID CVE-2026-43253

Severity High

CVSS score 7.5 / 10

CVSS version 3.1

Published 2026-05-06

Modified 2026-05-11

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43253?

CVE-2026-43253 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 , classified as an Improper Locking flaw (CWE-667) . It affects Linux kernel versions from 4.9 onward and has been patched in 6.6.128, 6.12.75, 6.18.16 and others. CVE-2026-43253 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43253?

CVE-2026-43253 has a CVSS score of 7.5 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-43253?

Yes. CVE-2026-43253 has been patched. Fixed versions include 6.6.128, 6.12.75, 6.18.16 and others. If you are running Linux kernel 4.9 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43253 actively exploited?

No. CVE-2026-43253 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.