CVE-2026-68175
Received Received - Intake

Resource Leak in Linux Kernel mmiotrace

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix resource leak on mmiotrace trace_pipe close The mmiotrace tracer was added May 12th 2008. At that time, resources created in pipe_open() could not be freed because there was not pipe_close function pointer of the tracer. The pipe_close function pointer was added in December 7th, 2009, but the mmiotrace tracer was not updated. mmio_pipe_open() allocates a header_iter and takes a pci_dev reference when trace_pipe is opened. mmio_close() frees them, but it was only wired to the tracer's .close callback. tracing_release_pipe() invokes .pipe_close, not .close, when the trace_pipe file is released. As a result, closing trace_pipe with the mmiotrace tracer active leaked the header_iter allocation and left a stale pci_dev reference. Set .pipe_close to mmio_close, matching how function_graph wires both callbacks to the same handler. Note, if the trace_pipe is read to completion, it will clean up the resources, but if one were to run: # head -n 1 /sys/kernel/tracing/trace_pipe VERSION 20070824 Over and over again, it would trigger a massive leak.

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Meta Information

Published
2026-08-10
Last Modified
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
CVE-2026-68175
EUVD
EUVD-2026-55276

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a resource leak in the Linux kernel's mmiotrace tracer. When trace_pipe is closed, the allocated header_iter and pci_dev reference are not freed properly because the tracer's .pipe_close callback was not set to mmio_close. This causes memory and reference leaks if trace_pipe is repeatedly accessed without reading to completion.

Detection Guidance

This vulnerability is specific to the Linux kernel's mmiotrace tracer and does not have network-based detection methods. To check if your system is affected, verify if the mmiotrace tracer is active or if the kernel version includes the vulnerable code path. Commands like 'ls /sys/kernel/tracing' or 'cat /proc/version' may help identify the kernel version.

Impact Analysis

This vulnerability can lead to memory leaks and resource exhaustion on systems using the mmiotrace tracer. Repeatedly accessing trace_pipe without full reads may cause the kernel to run out of memory or PCI device references, potentially leading to system instability or crashes.

Mitigation Strategies

Apply the latest kernel update that includes the fix for this vulnerability. If updating is not immediately possible, disable the mmiotrace tracer by ensuring it is not enabled in kernel configuration or runtime settings. Monitor kernel security advisories for patches.

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