CVE-2026-68175 tracing: Fix resource leak on mmiotrace trace_pipe close
Local attackers with high privileges can cause a resource leak and denial of service by repeatedly opening and closing the mmiotrace trace_pipe.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68175?
CVE-2026-68175 is a denial of service vulnerability in Linux, published on 10 Aug 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: 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.
Which versions are affected by CVE-2026-68175?
How do I fix CVE-2026-68175?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-68175 being exploited?
There is no known exploitation of CVE-2026-68175 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68175, DEBIAN-CVE-2026-68175, GHSA-frw4-mrvx-h68w, UBUNTU-CVE-2026-68175.