What is CVE-2026-43364?

CVE-2026-43364 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a NULL Pointer Dereference flaw (CWE-476), affecting Linux kernel versions from 6.16 onward and patched in 6.18.20, 6.19.9 and 7.0. CVE-2026-43364 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43364?

CVE-2026-43364 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-2026-43364?

Yes, CVE-2026-43364 has been patched. Fixed versions include 6.18.20, 6.19.9 and 7.0. If you are running Linux kernel 6.16 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43364 actively exploited?

CVE-2026-43364 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is NULL Pointer Dereference (CWE-476)?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/476.html

CVE-2026-43364

Medium

In the Linux kernel, the following vulnerability has been resolved: ublk: fix NULL pointer dereference in ublk_ctrl_set_size() ublk_ctrl_set_size() unconditionally dereferences ub->ub_disk via set_capacity_and_notify() without checking if it is NULL. ub->ub_disk is NULL before UBLK_CMD_START_DEV completes (it is only assigned in ublk_ctrl_start_dev()) and after UBLK_CMD_STOP_DEV runs (ublk_detach_disk() sets it to NULL). Since the UBLK_CMD_UPDATE_SIZE handler performs no state validation, a user can trigger a NULL pointer dereference by sending UPDATE_SIZE to a device that has been added but not yet started, or one that has been stopped. Fix this by checking ub->ub_disk under ub->mutex before dereferencing it, and returning -ENODEV if the disk is not available.

Package Linux Kernel

Published 2026-05-08

Last modified 2026-05-15

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-476

CVE-2026-43364 is a NULL Pointer Dereference vulnerability

What is NULL Pointer Dereference?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.16 and later are affected. Fixed in 6.18.20, 6.19.9, 7.0 and their respective stable series.

Affected from

≥ 6.16

Fixed in

✓ 6.18.20 6.18.x ✓ 6.19.9 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43364 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/25966fc097691e5c925ad080f64a2f19c5fd940a
Patch
Kernel patch commit
https://git.kernel.org/stable/c/c28d945bfa92e15147e93b73f95345b9bec979b0
Patch
Kernel patch commit
https://git.kernel.org/stable/c/f13fe6794726755a43090cb680c4c58cea6aa5f1
Patch

Details

CVE ID CVE-2026-43364

Severity Medium

CVSS score 5.5 / 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-2026-43364?

CVE-2026-43364 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . It affects Linux kernel versions from 6.16 onward and has been patched in 6.18.20, 6.19.9 and 7.0. CVE-2026-43364 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43364?

CVE-2026-43364 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-2026-43364?

Yes — CVE-2026-43364 has been patched. Fixed versions include 6.18.20, 6.19.9 and 7.0. If you are running Linux kernel 6.16 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43364 actively exploited?

No — CVE-2026-43364 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
What is NULL Pointer Dereference (CWE-476)?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. View CWE-476 on MITRE CWE →