CVE-2026-97923

Received Received - Intake

Memory Leak in Linux Kernel Tracing Subsystem

Publication date: 2026-09-25

Last updated on: 2026-10-03

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Free histogram the var ref when its initialization fails create_var_ref() allocates a VAR_REF hist_field and then calls init_var_ref() to fill it in. When that fails the field is leaked. commit 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy var_refs") made destroy_hist_field() return early for HIST_FIELD_FL_VAR_REF, since var refs are freed by walking the trigger's var_refs[] array instead. create_var_ref() adds the field to that array only after init_var_ref() has succeeded, so on this path the field is in neither place and nothing frees it. The call was correct when it was written, before var refs were taken out of destroy_hist_field(). init_var_ref() cannot free it either. The caller owns the field, so init_var_ref() undoes only its own string allocations and leaves the field alone. Freeing it there would leave create_var_ref() passing freed memory to destroy_hist_field(), which reads its flags. Call __destroy_hist_field(), which frees the field without consulting the flag.

CVSS Scores

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Meta Information

Published

2026-09-25

Last Modified

2026-10-03

Generated

2026-10-15

AI Q&A

2026-09-25

EPSS Evaluated

2026-10-14

NVD

CVE-2026-97923

EUVD

EUVD-2026-86777

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a memory leak in the tracing subsystem. When initializing a variable reference fails, the allocated memory for the reference is not freed properly. The issue occurs because the cleanup path was changed, but the initialization failure path was not updated accordingly, leaving the memory allocated and unreachable.

Detection Guidance

This vulnerability is specific to the Linux kernel's tracing subsystem and requires kernel-level inspection. Detection involves checking kernel logs for tracing-related errors or examining kernel memory for leaked VAR_REF hist_field objects. Use commands like 'dmesg | grep tracing' or 'cat /proc/kallsyms | grep create_var_ref' to inspect kernel functions. If custom kernel modules are used, review their interaction with tracing features.

Impact Analysis

This vulnerability could lead to memory exhaustion over time as the leaked memory accumulates. Systems running affected Linux kernel versions may experience performance degradation or crashes due to running out of available memory.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA as it is a memory leak in the Linux kernel's tracing subsystem. It does not involve data exposure or unauthorized access, which are primary concerns for these regulations.

Mitigation Strategies

Apply the latest Linux kernel patches from your distribution to resolve this issue. If patching is not immediately possible, disable tracing features via kernel boot parameters (e.g., 'tracing=off') or restrict access to tracing interfaces. Monitor kernel logs for errors related to tracing and update affected systems as soon as updates are available.

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