LiveActive security incident?Get immediate response
CVE Record

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

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.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2026-23309 is a Linux kernel tracing bug where an error path can crash by dereferencing a NULL pointer. The public record describes a code fix, but gives no CVSS score, CWE, or confirmed real-world exploitation. Treat it as kernel stability risk until your vendor maps it to shipped kernels.

Executive priority

Track this as a kernel maintenance item, not an emergency, unless your Linux vendor rates it higher for your deployed versions. The main business concern is potential system instability from a kernel NULL pointer dereference, with no sourced evidence of exploitation.

Technical view

If trigger_data_alloc() returns NULL, event_hist_trigger_parse() reaches out_free and calls trigger_data_free(). That helper previously dereferenced data->cmd_ops->set_filter without checking data. The fix adds a NULL check in trigger_data_free(). The record ties this to Linux kernel tracing and stable kernel commits.

Likely exposure

Exposure is likely limited to Linux systems running kernel builds that include the vulnerable tracing code path. The supplied data lists Linux kernel versions and stable commits but does not provide complete distro package ranges, CPEs, or exploit prerequisites.

Exploitation context

The bundle does not cite active exploitation, public exploit use, or CISA KEV listing. It describes a NULL pointer dereference discovered during review of stable backports, so exploitation context remains incomplete from the provided sources.

Researcher notes

The source record lacks CVSS, CWE, CPEs, attacker requirements, and complete affected range semantics. Analysis should focus on vendor backport mapping and whether unprivileged users can reach event histogram trigger parsing in deployed configurations.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fix commits.
  • Check distribution advisories for exact vulnerable and fixed package versions.
  • Prioritize systems where kernel tracing or debug facilities are available to users.
  • Apply normal kernel reboot procedures after installing fixed packages.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and containers with host kernel exposure.
  • Map installed vendor kernel packages to advisories referencing CVE-2026-23309.
  • Confirm the relevant stable fix commit is present in your kernel source package.
  • Review security monitoring for kernel crash or tracing-related fault reports.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2026-23309 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
7Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxc10f0efe57728508d796ae4ba7abe4c14ec3d8ef, 7e6556e9329bc484e9dcdab6e346d959267c0636, 9b0513905e0598b9f8cfccab8e47497aed5d935d, 335dfe4bc6368e70e8c15419375cf609c4f85558, e42efbe9754da78eafe11f6bd3ca9c8a094a752a, 0550069cc25f513ce1f109c88f7c1f01d63297dbunaffected
LinuxLinux6.1.165, 6.6.128, 6.12.75, 6.18.14, 6.19.4unaffected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.