Critical

Remote Code Execution in Azure Managed Instance for Apache Cassandra

IdentifiersCVE-2026-33109CWE-284· Improper Access Control

CVE-2026-33109 is an improper access control vulnerability in Azure Managed Instance for Apache Cassandra. According to the provided content, the flaw allows an authorized attacker to execute code over a network. The vulnerability is classified as CWE-284 and is described by Microsoft as affecting an exclusively hosted Azure service. The supplied CVSS v3.1 vector is AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H, indicating network reachability, low attack complexity, low privileges required, no user interaction, and high impact to confidentiality, integrity, and availability with scope change.

For your environment

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows remote code execution within the affected Azure Managed Instance for Apache Cassandra service context. Based on the provided CVSS vector and descriptions, impact can include compromise of confidentiality, integrity, and availability, with high-severity effects and changed scope. An attacker with valid low-privilege access could potentially run arbitrary code against the service over the network.

Mitigation

If you can’t patch tonight, do this now.

Because this is an exclusively hosted Azure service vulnerability that Microsoft states has been fully mitigated, there is no direct customer-side mitigation required. Where organizations want additional risk reduction, the provided content recommends restricting network access to Azure Cassandra instances, enforcing least privilege, and increasing monitoring and logging around exposed cloud services until service-side remediation status is confirmed.

Remediation

Patch, then assume compromise.

Microsoft has already mitigated this vulnerability in the hosted service. The provided content states that this issue requires no customer action and that users of the service do not need to take action. Organizations should nevertheless follow Azure portal guidance and MSRC advisories for confirmation of service status in their region or cluster.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Microsoft CorporationAzure Managed Instance For Apache Cassandraapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

16 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

16 SOURCESView more in app

arctic wolf blogNews

May 16, 2026

Microsoft Patch Tuesday: May 2026 - Arctic Wolf

A vulnerability affecting Azure Managed Instance for Apache Cassandra that is prioritized for patching in May 2026.

arctic wolf blogNews

May 16, 2026

Microsoft Patch Tuesday: May 2026 - Arctic Wolf

A vulnerability affecting Azure Managed Instance for Apache Cassandra, prioritized for patching in May 2026.

the hacker newsNews

May 13, 2026

Microsoft Patches 138 Vulnerabilities, Including DNS and Netlogon RCE Flaws

An improper access control vulnerability in Azure Managed Instance for Apache Cassandra that allows authorized remote code execution.

cyberscoopNews

May 12, 2026

Microsoft addresses 137 vulnerabilities in May’s Patch Tuesday, including 13 rated critical | CyberScoop

A critical vulnerability affecting Azure, disclosed by Microsoft as part of Patch Tuesday.

+3 more in the timeline

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity9

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-33109

NVD

nvd.nist.gov/vuln/detail/CVE-2026-33109

MITRE CWE · CWE-284

Improper Access Control

Vendor Advisory

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33109