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Fencer Intel
critical 9.8

CVE-2026-66801 json

Microsoft Xbox Remote Code Execution Vulnerability

published yesterday modified 16h ago also EUVD-2026-121540

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

Heap-based buffer overflow in Xbox allows an unauthorized attacker to execute code over a network.

Patch / fix

  • Microsoft Microsoft GDK 2610

Is CVE-2026-66801 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-66801 updated cvss 9.9

multicluster-global-hub: Cross-hub lateral movement via shared spec-topic Write ACL and spoofable CloudEvent identity

  • Red Hat Multicluster Global Hub 1.4.9 multicluster-globalhub/multicluster-globalhub-rhel9-operator 1786621416
    fixed: vendor fix RHSA-2026:55810
  • Red Hat Multicluster Global Hub 1.5.8 multicluster-globalhub/multicluster-globalhub-rhel9-operator 1786621343
    fixed: vendor fix RHSA-2026:54577
  • Red Hat Multicluster Global Hub 1.6.6 multicluster-globalhub/multicluster-globalhub-rhel9-operator 1786071343
    fixed: vendor fix RHSA-2026:54392
  • Red Hat Multicluster Global Hub 1.7.4 multicluster-globalhub/multicluster-globalhub-rhel9-operator 1785773214
    fixed: vendor fix RHSA-2026:53530
  • Red Hat Multicluster Global Hub 1.8.2 multicluster-globalhub/multicluster-globalhub-rhel9-operator 1786067967
    fixed: vendor fix RHSA-2026:52946
  • Red Hat Multicluster Global Hub 1.4.9 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1786621693, multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1786621960, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1786621455, multicluster-globalhub/multicluster-globalhub-operator-bundle 1786623856, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1786621340 Red Hat Multicluster Global Hub 1.5.8 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1786621379, multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1786621682, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1786621626, multicluster-globalhub/multicluster-globalhub-operator-bundle 1786623440, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1786621234 Red Hat Multicluster Global Hub 1.6.6 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1786068047, multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1785863006, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1786068507, multicluster-globalhub/multicluster-globalhub-operator-bundle 1786072360, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1785973305 Red Hat Multicluster Global Hub 1.7.4 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1785775948, multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1785442872, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1785773056, multicluster-globalhub/multicluster-globalhub-operator-bundle 1785780023 Red Hat Multicluster Global Hub 1.8.2 multicluster-globalhub/multicluster-globalhub-agent-rhel9 1785763319, multicluster-globalhub/multicluster-globalhub-grafana-rhel9 1785443657, multicluster-globalhub/multicluster-globalhub-manager-rhel9 1785547017, multicluster-globalhub/multicluster-globalhub-operator-bundle 1786372816, multicluster-globalhub/multicluster-globalhub-postgres-exporter-rhel9 1785973181
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
yesterday

Exploit prediction

1.13% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Microsoft Microsoft GDK

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.