CVE-2026-23309 tracing: Add NULL pointer check to trigger_data_free()

What is CVE-2026-23309?

CVE-2026-23309 is a medium-severity vulnerability in Linux kernel, published on 25 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-476

Which versions are affected by CVE-2026-23309?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-23309?

Apply the vendor's patch.

Is CVE-2026-23309 being exploited?

There is no known exploitation of CVE-2026-23309 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-23309, DEBIAN-CVE-2026-23309, GHSA-f7v6-c4j6-g8wv, UBUNTU-CVE-2026-23309.