What is CVE-2026-43021?

CVE-2026-43021 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a Memory Leak flaw (CWE-401), affecting Linux kernel versions from 6.19 onward and patched in 6.19.12 and 7.0. CVE-2026-43021 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43021?

CVE-2026-43021 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-43021?

Yes, CVE-2026-43021 has been patched. Fixed versions include 6.19.12 and 7.0. If you are running Linux kernel 6.19 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43021 actively exploited?

CVE-2026-43021 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Memory Leak (CWE-401)?

The product does not release memory after use, causing gradual resource exhaustion. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/401.html

CVE-2026-43021

Medium

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix leaks when hci_cmd_sync_queue_once fails When hci_cmd_sync_queue_once() returns with error, the destroy callback will not be called. Fix leaking references / memory on these failures.

Package Linux Kernel

Published 2026-05-01

Last modified 2026-05-08

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-401

CVE-2026-43021 is a Memory Leak vulnerability

What is Memory Leak?

The product does not release memory after use, causing gradual resource exhaustion. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.19 and later are affected. Fixed in 6.19.12, 7.0 and their respective stable series.

Affected from

≥ 6.19

Fixed in

✓ 6.19.12 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43021 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/7fd74178d4b16dcf47179da634ea9d7c02e3608b
Patch
Kernel patch commit
https://git.kernel.org/stable/c/aca377208e7f7322bf4e107cdec6e7d7e8aa7a88
Patch

Details

CVE ID CVE-2026-43021

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-05-01

Modified 2026-05-08

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43021?

CVE-2026-43021 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a Memory Leak flaw (CWE-401) . It affects Linux kernel versions from 6.19 onward and has been patched in 6.19.12 and 7.0. CVE-2026-43021 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43021?

CVE-2026-43021 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-43021?

Yes — CVE-2026-43021 has been patched. Fixed versions include 6.19.12 and 7.0. If you are running Linux kernel 6.19 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43021 actively exploited?

No — CVE-2026-43021 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
What is Memory Leak (CWE-401)?

The product does not release memory after use, causing gradual resource exhaustion. View CWE-401 on MITRE CWE →