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NVD / CVE Program· CNA Linux

CVE-2026-93181: perf/x86/intel/uncore: Fix uncore_box ref/unref ordering

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
  • Fixed version: Linux Linux 174f0582e38abe03b88e15f04bfe58490f88cb19, 3cfd351602e6704cce9bc766a974afb9f745d44b, 64aa1bb4017d598828c6d8cd718f43daf2a83375.

Low priority for now. Upgrade to Linux Linux 174f0582e38abe03b88e15f04bfe58490f88cb19, 3cfd351602e6704cce9bc766a974afb9f745d44b, 64aa1bb4017d598828c6d8cd718f43daf2a83375 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 21, 2026
EPSS
0.2% · 10th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.11affected
    • c74443d92f68f07c03ae242ced554b749e6c6736 and later · before 3cfd351602e6704cce9bc766a974afb9f745d44baffected · git
    • c74443d92f68f07c03ae242ced554b749e6c6736 and later · before 64aa1bb4017d598828c6d8cd718f43daf2a83375affected · git
    • c74443d92f68f07c03ae242ced554b749e6c6736 and later · before 174f0582e38abe03b88e15f04bfe58490f88cb19affected · git
    • before 6.11not affected · semver
    • 6.12.114 and later · up to and including 6.12.*not affected · semver
    • 7.2.6 and later · up to and including 7.2.*not affected · semver
    • 7.3 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13linuxfrom 0—
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-93179Sep 17, 2026 · drm/amd/powerplay: fix VoltageObjectInfo zero-stride loop and OOB read
    0Monitor
  • ← EarlierCVE-2026-93180Sep 17, 2026 · drm/panthor: Fix NPD issue on partial unmap of an evicted BO
    0Monitor
  • Later →CVE-2026-93182Sep 17, 2026 · sched/fair: Fix overflow in update_tg_cfs_runnable()
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux174f0582e38abe03b88e15f04bfe58490f88cb19Vendor (CNA)
Linux Linux3cfd351602e6704cce9bc766a974afb9f745d44bVendor (CNA)
Linux Linux64aa1bb4017d598828c6d8cd718f43daf2a83375Vendor (CNA)
debian:linux7.2.6-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

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No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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