CVE-2026-66803Network attack vector

Unauthenticated remote code execution

Published Jul 30, 2026 · Updated Jul 30, 2026

Improper access control in Microsoft Azure Cosmos DB allows remote attackers to execute code through the hosted service over a network. Microsoft has not disclosed the affected component or the access-control operation that mishandles network requests. No credentials or user interaction are required, but the public record does not establish a Gremlin sandbox escape, file access, or cross-tenant database access.

CVSS severity10.0
Critical
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Microsoft Azure Cosmos DB allows remote attackers to execute code through the hosted service over a network. Microsoft has not disclosed the affected component or the access-control operation that mishandles network requests. No credentials or user interaction are required, but the public record does not establish a Gremlin sandbox escape, file access, or cross-tenant database access.

The record

CVE
CVE-2026-66803
Published
Jul 30, 2026
Updated
Jul 30, 2026
Vendor
Microsoft
Product
Azure Cosmos DB
Classifications
CWE-284, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=-

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Azure Cosmos DBversion=-

Published CVSS scores

10.0Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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