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Fencer Vulns
high 8.8

CVE-2026-66805 json

Microsoft SharePoint Server Remote Code Execution Vulnerability

published 2026-08-11 2 mo ago modified 2026-10-30 9 d ago also EUVD-2026-56747

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

Patch / fix

  • Microsoft Microsoft SharePoint Server Subscription Edition 16.0.20326.20190

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-2026-66805 updated cvss 8.0

console: Stored DOM XSS via unescaped pod logs in document.write

  • Red Hat multicluster engine for Kubernetes 2.6 multicluster-engine/console-mce-rhel9 1787264250
    fixed: vendor fix RHSA-2026:59579
  • Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/console-mce-rhel9 1787259048
    fixed: vendor fix RHSA-2026:59558
  • Red Hat multicluster engine for Kubernetes 2.9 multicluster-engine/console-mce-rhel9 1787079359
    fixed: vendor fix RHSA-2026:59559
  • Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/console-mce-rhel9 1786548913
    fixed: vendor fix RHSA-2026:54432
  • Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/console-mce-rhel9 1786911977
    fixed: vendor fix RHSA-2026:57194
  • Red Hat multicluster engine for Kubernetes 2.17 multicluster-engine/console-mce-rhel9 1786668856
    fixed: vendor fix RHSA-2026:59593
  • Red Hat Advanced Cluster Management for Kubernetes 2.11 rhacm2/console-rhel9 1787687062
    fixed: vendor fix RHSA-2026:60387
  • Red Hat Advanced Cluster Management for Kubernetes 2.13 rhacm2/console-rhel9 1787339249
    fixed: vendor fix RHSA-2026:60390
show 5 more
  • Red Hat Advanced Cluster Management for Kubernetes 2.14 rhacm2/console-rhel9 1787339248
    fixed: vendor fix RHSA-2026:60388
  • Red Hat Advanced Cluster Management for Kubernetes 2.15 rhacm2/console-rhel9 1786547771
    fixed: vendor fix RHSA-2026:54427
  • Red Hat Advanced Cluster Management for Kubernetes 2.16 rhacm2/console-rhel9 1787339213
    fixed: vendor fix RHSA-2026:60391
  • Red Hat Advanced Cluster Management for Kubernetes 2.17 rhacm2/console-rhel9 1787335105
    fixed: vendor fix RHSA-2026:60386
  • Red Hat multicluster engine for Kubernetes 2.6 multicluster-engine/hive-rhel9 1787291123, multicluster-engine/work-rhel9 1787263188, multicluster-engine/discovery-rhel9 1787263531, multicluster-engine/placement-rhel9 1787260699, multicluster-engine/must-gather-rhel9 1787264198, multicluster-engine/registration-rhel9 1787259957, +20 more Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/hive-rhel9 1787291250, multicluster-engine/work-rhel9 1787259113, multicluster-engine/discovery-rhel9 1787259074, multicluster-engine/placement-rhel9 1787259108, multicluster-engine/must-gather-rhel9 1787258992, multicluster-engine/registration-rhel9 1787259114, +20 more Red Hat multicluster engine for Kubernetes 2.9 multicluster-engine/hive-rhel9 1787205132, multicluster-engine/work-rhel9 1786933545, multicluster-engine/discovery-rhel9 1786658519, multicluster-engine/placement-rhel9 1786491555, multicluster-engine/must-gather-rhel9 1786837240, multicluster-engine/registration-rhel9 1786977984, +23 more Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/hive-rhel9 1786549045, multicluster-engine/work-rhel9 1786548903, multicluster-engine/discovery-rhel9 1786549437, multicluster-engine/placement-rhel9 1786548467, multicluster-engine/must-gather-rhel9 1786548899, multicluster-engine/registration-rhel9 1786548900, +24 more Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/hive-rhel9 1786947450, multicluster-engine/work-rhel9 1786907276, multicluster-engine/discovery-rhel9 1786911975, multicluster-engine/placement-rhel9 1786911984, multicluster-engine/must-gather-rhel9 1786911926, multicluster-engine/registration-rhel9 1786911975, +25 more Red Hat multicluster engine for Kubernetes 2.17 multicluster-engine/hive-rhel9 1787033495, multicluster-engine/work-rhel9 1786933423, multicluster-engine/maestro-rhel9 1786985023, multicluster-engine/discovery-rhel9 1786681989, multicluster-engine/placement-rhel9 1786983381, multicluster-engine/must-gather-rhel9 1786837119, +28 more
    +6 more products
    Red Hat Advanced Cluster Management for Kubernetes 2.11 rhacm2/thanos-rhel9 1787685239, rhacm2/prometheus-rhel9 1787261499, rhacm2/acm-grafana-rhel9 1787682482, rhacm2/acm-search-v2-rhel9 1787688827, rhacm2/node-exporter-rhel9 1787263326, rhacm2/observatorium-rhel9 1787263596, +34 more Red Hat Advanced Cluster Management for Kubernetes 2.13 rhacm2/thanos-rhel9 1787263906, rhacm2/acm-cli-rhel9 1787259085, rhacm2/prometheus-rhel9 1787263757, rhacm2/acm-grafana-rhel9 1787644958, rhacm2/acm-search-v2-rhel9 1787682112, rhacm2/node-exporter-rhel9 1787263178, +37 more Red Hat Advanced Cluster Management for Kubernetes 2.14 rhacm2/thanos-rhel9 1787614805, rhacm2/acm-cli-rhel9 1786923505, rhacm2/prometheus-rhel9 1786976997, rhacm2/acm-grafana-rhel9 1787645355, rhacm2/acm-search-v2-rhel9 1787682033, rhacm2/node-exporter-rhel9 1787233241, +37 more Red Hat Advanced Cluster Management for Kubernetes 2.15 rhacm2/thanos-rhel9 1786549663, rhacm2/acm-cli-rhel9 1786547726, rhacm2/prometheus-rhel9 1786547911, rhacm2/acm-grafana-rhel9 1786549752, rhacm2/acm-search-v2-rhel9 1786547826, rhacm2/node-exporter-rhel9 1786547812, +39 more Red Hat Advanced Cluster Management for Kubernetes 2.16 rhacm2/thanos-rhel9 1786909435, rhacm2/acm-cli-rhel9 1786908319, rhacm2/prometheus-rhel9 1786909036, rhacm2/acm-grafana-rhel9 1787645431, rhacm2/acm-search-v2-rhel9 1787681686, rhacm2/node-exporter-rhel9 1786908949, +40 more Red Hat Advanced Cluster Management for Kubernetes 2.17 rhacm2/thanos-rhel9 1787229716, rhacm2/acm-cli-rhel9 1787227626, rhacm2/prometheus-rhel9 1787230287, rhacm2/acm-grafana-rhel9 1787316467, rhacm2/acm-search-v2-rhel9 1787681651, rhacm2/node-exporter-rhel9 1787230187, +39 more
    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
no
Technical impact
total
Assessed
3 mo ago

Exploit prediction

2.04% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Microsoft Microsoft SharePoint Server Subscription Edition

Classification

Weakness
  • CWE-502 Deserialization of Untrusted Data

References

Sources

Fencer Vulns 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.