CVE-2026-93181
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Received - Intake
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Vulnerability report for CVE-2026-93181, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-17
Last updated on: 2026-09-17
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
perf/x86/intel/uncore: Fix uncore_box ref/unref ordering
In uncore_event_cpu_online(), uncore_box_ref() was called before
uncore_change_context(). uncore_box_ref() gates on box->cpu >= 0,
but box->cpu is still -1 at that point because uncore_change_context()
has not run yet. As a result, the box is never initialized on the
first CPU to come online in a die, leaving it permanently
uninitialized in the single-CPU-per-die case.
Thus, box->refcnt is one count below the true value, and in the CPU
offline path, the box will be torn down on the second-to-last CPU.
In uncore_event_cpu_offline(), uncore_box_unref() was called after
uncore_change_context(), so box->cpu is already -1 when the collector
CPU goes offline, which prevents it from tearing down the box.
Fix by swapping the call order in both paths so that
uncore_box_{ref,unref}() runs at the point where box->cpu reflects
the correct context.
Move allocate_boxes() out of uncore_box_ref() to enable this
reordering.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
