What is CVE-2026-69399?

CVE-2026-69399 is a critical-severity vulnerability in Microsoft Azure Arc, classified under Unintended Proxy or Intermediary (Confused Deputy). CVSS score: 9.9/10. Published 2026-09-17.

How severe is CVE-2026-69399?

Critical severity. CVSS v3 base score is 9.9 out of 10.

Vulnerability in Microsoft Azure Arc

CVE-2026-69399

Unintended proxy or intermediary in Azure Arc allows an authorized attacker to elevate privileges over a network.

Published 2026-09-17 · last modified 2026-10-31.

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (48.2th percentile), scored 2026-11-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.001

Affected products

Weakness classification (CWE)

CWE-441 — Unintended Proxy or Intermediary (Confused Deputy)

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69399 (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-69399?: CVE-2026-69399 is a critical-severity vulnerability in Microsoft Azure Arc, classified under Unintended Proxy or Intermediary (Confused Deputy). CVSS score: 9.9/10. Published 2026-09-17.
How severe is CVE-2026-69399?: Critical severity. CVSS v3 base score is 9.9 out of 10.