What is CVE-2026-23309?

CVE-2026-23309 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 6.1.165 onward and patched in 6.1.167, 6.6.130, 6.12.77 and others. CVE-2026-23309 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-23309?

CVE-2026-23309 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-2026-23309?

Yes, CVE-2026-23309 has been patched. Fixed versions include 6.1.167, 6.6.130, 6.12.77 and others. If you are running Linux kernel 6.1.165 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-23309 actively exploited?

CVE-2026-23309 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-2026-23309

Medium

In the Linux kernel, the following vulnerability has been resolved: tracing: Add NULL pointer check to trigger_data_free() If trigger_data_alloc() fails and returns NULL, event_hist_trigger_parse() jumps to the out_free error path. While kfree() safely handles a NULL pointer, trigger_data_free() does not. This causes a NULL pointer dereference in trigger_data_free() when evaluating data->cmd_ops->set_filter. Fix the problem by adding a NULL pointer check to trigger_data_free(). The problem was found by an experimental code review agent based on gemini-3.1-pro while reviewing backports into v6.18.y.

Package Linux Kernel

Published 2026-03-25

Last modified 2026-05-28

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-2026-23309 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 6.1.165, 6.6.128, 6.12.75, 6.18.14, 6.19.4 and later are affected. Fixed in 6.1.167, 6.6.130, 6.12.77, 6.18.17, 6.19.7 and their respective stable series.

Affected from

≥ 6.1.165 ≥ 6.6.128 ≥ 6.12.75 ≥ 6.18.14 ≥ 6.19.4

Fixed in

✓ 6.1.167 6.1.x ✓ 6.6.130 6.6.x ✓ 6.12.77 6.12.x ✓ 6.18.17 6.18.x ✓ 6.19.7 6.19.x

References

6 total

Kernel Git
https://git.kernel.org/stable/c/13dcd9269e225e4c4ceabdaeebe2ce4661b54c6e

Patch
Kernel Git
https://git.kernel.org/stable/c/2ce8ece5a78da67834db7728edc801889a64f643

Patch
Kernel Git
https://git.kernel.org/stable/c/42b380f97d65e76e7b310facd525f730272daf57

Patch
Kernel Git
https://git.kernel.org/stable/c/457965c13f0837a289c9164b842d0860133f6274

Patch
Kernel Git
https://git.kernel.org/stable/c/477469223b2b840f436ce204333de87cb17e5d93

Patch

Showing 5 of 6 references View all on NVD

Details

CVE ID CVE-2026-23309

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-03-25

Modified 2026-05-28

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-23309?

CVE-2026-23309 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 6.1.165 onward and has been patched in 6.1.167, 6.6.130, 6.12.77 and others. CVE-2026-23309 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-23309?

CVE-2026-23309 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-2026-23309?

Yes. CVE-2026-23309 has been patched. Fixed versions include 6.1.167, 6.6.130, 6.12.77 and others. If you are running Linux kernel 6.1.165 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-23309 actively exploited?

No. CVE-2026-23309 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.