CVSS 10.0CVSS 10.0 · CRITICAL

CVE-2026-66803RCE via Improper Access Control in Azure Cosmos DB

Improper access control in Azure Cosmos DB allows an unauthorized attacker to execute code over a network.

Analysis

Una vulnerabilidad crítica de control de acceso en Azure Cosmos DB permite a un atacante no autorizado ejecutar código de forma remota a través de la red. Este fallo afecta directamente a las aplicaciones que utilizan este motor NoSQL en la nube, comprometiendo la seguridad del backend y la integridad del entorno de ejecución.

Relevant roles

CloudBackendNosqlCyberSecurity

Severity

Score: 10.0(CRITICAL)

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

AV: NETWORK

AC: LOW

PR: NONE

UI: NONE

S: CHANGED

C: HIGH

I: HIGH

A: HIGH

Weakness (CWE): CWE-284

EPSS

Probability of exploitation (next 30 days): 0.0049 (0.5%)

Percentile: 39.7%

EPSS: 2026-08-04

Affects

microsoft:azure_cosmos_db

Technical description

Improper access control in Azure Cosmos DB allows an unauthorized attacker to execute code over a network.

Published: 7/30/2026, 9:18:12 PM

Last modified: 8/4/2026, 8:46:44 PM

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66803

How to read this card

Actively exploited

KEV (Known Exploited Vulnerabilities) is CISA's catalog of CVEs confirmed as actively exploited in the real world. If a CVE is on KEV, someone is already using it in attacks.

CVSS 10.0

CVSS 10.0 — the theoretical maximum severity. Remotely exploitable, no privileges required, total impact. Not yet confirmed as exploited in the wild, but patch now. Widely used software only: a 10.0 in a niche plugin does not make it here.

AI-recommended

A language model reviewed the CVE and judged that it affects widely deployed software or common developer tooling. A human on the team approved publication before it landed here.

Impact categories the AI evaluates

widely_deployed_infra — Linux kernel, OpenSSL, glibc, k8s, Docker, nginx, OpenSSH.

popular_dev_tooling — Node.js, Python, Go, React, Next.js, common npm/pip libraries.

common_consumer_software — Chrome, Firefox, Windows, macOS, popular mobile apps.

enterprise_saas — GitHub, GitLab, Atlassian, Salesforce, Cisco, Fortinet, Ivanti.

niche_software — Regional CMSs, hobby tools, rarely used libraries.

not_relevant — Vendor-specific firmware, discontinued software.

EPSS — EPSS (Exploit Prediction Scoring System) by FIRST.org estimates the probability that a CVE will be exploited in the next 30 days. Range is 0 to 1; very fresh CVEs typically score low until evidence accumulates.