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Azure Managed Instance for Apache Cassandra CVE-2026-33109

| EUVDEUVD-2026-28448 CRITICAL
Improper Access Control (CWE-284)
2026-05-07 microsoft GHSA-g4xx-6vv3-3x48
9.9
CVSS 3.1 · Vendor: microsoft
Temporal: 8.6
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain low-privilege Cassandra credentials
  2. Delivery
    Send crafted network request to managed instance
  3. Exploit
    Exploit access control flaw
  4. Execution
    Execute code on Azure infrastructure
  5. Persist
    Escape container scope
  6. Impact
    Access cross-tenant resources

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires valid authenticated credentials with low-privilege access to Azure Managed Instance for Apache Cassandra (PR:L from CVSS vector). The 'authorized attacker' language in the description confirms attackers must first obtain legitimate user credentials through phishing, credential stuffing, insider threat, or compromise of applications with database access. No special Cassandra feature enablement, non-default configuration, or user interaction (UI:N) required beyond baseline authenticated network access. The improper access control flaw (CWE-284) exists in default service configurations. Limiting factors for exploitation: authentication barrier prevents anonymous internet-based attacks, requiring attackers to target credential theft as prerequisite step. Network accessibility (AV:N) and low complexity (AC:L) mean authenticated attackers can exploit remotely without specialized conditions once credentials are obtained.

Impact

Critical real-world risk based on converging threat signals. CVSS 9.9 with AV:N/AC:L indicates network-accessible exploitation with low complexity, requiring only low-privileged authenticated access (PR:L). The Changed Scope (S:C) elevates severity significantly - attackers breach authorization boundaries to impact resources outside the vulnerable component, potentially accessing other customers' data in a multi-tenant cloud environment. Complete impact triad (C:H/I:H/A:H) enables full system compromise. However, exploitation requires authentication, creating a meaningful barrier absent in PR:N vulnerabilities. No CISA KEV listing or EPSS score provided, suggesting either recent disclosure or limited observed exploitation activity to date. Patch availability from Microsoft (RL:O) enables immediate risk mitigation. Primary risk factors: multi-tenant cloud service with scope escape potential, authentication bypass capability, and complete post-exploitation impact. Mitigating factors: authentication prerequisite limits attack surface to credential holders or those who first compromise valid accounts. Priority for organizations using Azure Managed Cassandra: immediate patching required given cloud service scope escape implications.

Exploit ScenarioDerived

An attacker with valid low-privilege credentials to an Azure Managed Cassandra instance (such as a compromised database application account or malicious insider) sends crafted network requests exploiting the access control flaw. The improper authorization check allows the attacker to bypass security boundaries and execute arbitrary code on the underlying Azure infrastructure hosting the Cassandra service. Leveraging the changed scope vulnerability, the attacker escapes the database container to access Azure management plane or neighboring customer instances, exfiltrating sensitive data, deploying ransomware, or establishing persistent backdoors across the cloud environment.

Monitor Track and reassess. Why: Vendor states no customer action required.
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – May 07, 2026

Remote code execution in Azure Managed Instance for Apache Cassandra allows authenticated attackers with low privileges to execute arbitrary code across tenant boundaries. The vulnerability involves improper access control (CWE-284) enabling scope escape with complete compromise of confidentiality, integrity, and availability. Microsoft has released a patch per MSRC advisory. CVSS 9.9 (Critical) reflects network-based attack with low complexity, low privileges required, and changed scope indicating container/tenant escape potential.

RemediationAI

Apply vendor-released patch per Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33109. As a fully managed Azure service, patching is typically performed by Microsoft through service updates rather than customer-initiated upgrades - consult the MSRC advisory for service update timeline and any required customer actions. Until patching is complete, implement compensating controls: restrict network access to Azure Managed Cassandra instances using Azure Network Security Groups or Private Endpoints to trusted IP ranges only, eliminating public internet exposure (mitigates AV:N attack vector but impacts legitimate remote access). Review and minimize privileged user accounts with Cassandra database access, enforcing principle of least privilege and multi-factor authentication for all accounts (reduces PR:L attack surface but requires operational overhead). Audit access logs for unauthorized code execution attempts or unusual cross-tenant activity patterns. Enable Azure Defender for Cloud alerts on Cassandra instances to detect exploitation indicators.

Affected VersionsENISA

Azure Managed Instance for Apache Cassandra - (version not specified)

Affected Packages

microsoft azure_managed_instance_for_apache_cassandra fix: Azure Managed Instance for Apache Cassandra

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in microsoft

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Azure Managed Instance for Apache Cassandra is Microsoft's fully managed cloud service for Apache Cassandra databases, providing automated deployment, scaling, and maintenance. The vulnerability stems from CWE-284 (Improper Access Control), a broad weakness class covering insufficient authorization checks, privilege validation failures, or security boundary enforcement gaps. In multi-tenant cloud environments like Azure, access control flaws can enable lateral movement between customer instances or privilege escalation from database user to underlying infrastructure. The Changed Scope (S:C) in the CVSS vector indicates the vulnerability affects resources beyond the vulnerable component's authorization scope, suggesting potential container escape, cross-tenant access, or cloud infrastructure compromise. Tags reference 'Authentication Bypass' alongside 'Apache' and 'Microsoft', indicating the flaw may allow circumventing authentication boundaries in the Cassandra service layer or Azure management plane.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 9.9 CRITICAL
AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
ENISA EUVD HIGH
CIRCL (temporal) 8.6 HIGH

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

Improper access control in Azure Managed Instance for Apache Cassandra allows an authorized attacker to execute code over a network.

Executive ViewAI

Why It Matters

Azure Managed Instance for Apache Cassandra contains a critical remote code execution vulnerability (CVE-2026-33109, CVSS 9.9) that allows low-privileged authenticated users to escape tenant boundaries and execute arbitrary code, potentially compromising data confidentiality, integrity, and availability across customer environments. Organizations running this managed service must apply the available patch immediately to prevent unauthorized cross-tenant access and data compromise.

Business Impact: Severe
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.1%
Top 82% exploitable
Threat Intel
2
1 sources
Vendor Action
No Action
Not required. The vulnerability documented by this CVE requires no customer action to resolve.
Vendor Status
Publicly Disclosed:No
Exploited:No
Service Type
Hosted
Vendor-managed, no client patch needed
Social Media
2
Sightings
Data Quality
8 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
Vendor states no customer action required
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
Very High
Technical Impact
Total

Priority Score

55
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +50
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: +5

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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