Introduction
CVE-2026-42822 is a maximum-severity authentication bypass in Microsoft Azure Local Disconnected Operations. It gives anyone with network access and basic identity context a path to full privilege escalation. The flaw carries a CVSS 3.1 base score of 10.0, and its scope change means the impact extends beyond the vulnerable component's own security boundary. That makes it one of the more consequential Azure vulnerabilities disclosed this year.
Azure Local Disconnected Operations (ALDO) is a specialized offering that extends Azure management to environments running in isolated or air-gapped configurations. It is designed for places where persistent cloud connectivity is unavailable, such as classified networks, remote industrial sites, or sovereign deployments. Because ALDO manages infrastructure in sensitive, disconnected environments, an authentication bypass in this component carries outsized risk.
Technical Information
Root Cause
CVE-2026-42822 is classified under CWE-287: Improper Authentication. The vulnerability is in the authentication mechanism of Azure Local Disconnected Operations, and it lets an unauthorized attacker elevate privileges over a network. Neither Microsoft nor the NVD has disclosed the exact authentication flow failure or the specific code path involved in their public advisories.
CVSS Breakdown
The full CVSS 3.1 vector string is:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
Breaking this down:
| Metric | Value | Meaning |
|---|---|---|
| Attack Vector | Network (AV:N) | Exploitable over the network |
| Attack Complexity | Low (AC:L) | No special conditions required |
| Privileges Required | None (PR:N) | No authentication needed |
| User Interaction | None (UI:N) | No victim action required |
| Scope | Changed (S:C) | Impact extends beyond the vulnerable component |
| Confidentiality | High (C:H) | Full information disclosure possible |
| Integrity | High (I:H) | Complete modification of data possible |
| Availability | High (A:H) | Total denial of service possible |
| Exploit Code Maturity | Unproven (E:U) | No known exploit code |
| Remediation Level | Official Fix (RL:O) | Vendor patch available |
The scope change metric means successful exploitation can affect resources managed by a different security authority than the vulnerable ALDO component itself. In practice, an attacker who bypasses authentication in ALDO could reach restricted information or perform operations normally limited to highly privileged administrators across the managed environment.
Attack Flow
The CVSS score reflects a network attack vector and no required privileges, but Microsoft's advisory adds context about how exploitation would realistically happen:
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The attacker must first gain access to the internal network where the ALDO environment operates. ALDO is built to run in isolated configurations, so an external attacker faces a significant barrier at this stage.
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The attacker needs relevant identity information, such as tenant identifiers, user identifiers, credentials, or tokens. Full authentication is not required. The attacker needs only enough context to interact with the authentication mechanism in a way that triggers the bypass.
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The attacker exploits the improper authentication flaw to elevate privileges without proper authorization checks.
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With elevated privileges, the attacker can access restricted information, modify configurations, or perform administrative operations across the ALDO-managed environment. The scope change in the CVSS vector confirms that the impact is not limited to the ALDO component alone.
Microsoft stresses that the most realistic scenario is a malicious or compromised insider who already has internal network access and some degree of identity context. That fits the threat model for air-gapped and disconnected environments, where the primary risk is typically an insider or a supply-chain compromise rather than a remote, internet-based attacker.
Data Gaps
Current public advisories do not provide root-cause code details, the exact authentication flow that fails, or proof-of-concept exploit code. The NVD and MSRC advisories describe the architectural impact at a high level but do not detail the precise mechanism.
Patch Information
Microsoft has released an official fix for CVE-2026-42822. The CVE.org record tags the MSRC advisory as both vendor-advisory and patch, and the CVSS temporal metrics set Remediation Level to Official Fix (RL:O).
The patch takes two forms, depending on the deployment model.
Azure Resource Manager (ARM) customers are already protected. Microsoft has deployed the mitigation on the server side across all Microsoft-operated Azure environments, so cloud-hosted instances need no customer action.
Azure Local Disconnected Operations (ALDO) customers must act. The fix ships as a full system update, not a standalone incremental patch, and customers must apply it through the Azure portal. The target version is 2604 or later, and the patched build is 2604.2.25645.
| Environment Type | Vulnerability Status | Required Customer Action | Fix Vehicle |
|---|---|---|---|
| Azure Resource Manager | Mitigated by Microsoft | None | Microsoft backend update |
| Azure Local Disconnected Operations | Vulnerable (versions 1.0.0 before 2604.2.25645) | Required | Full system update via Azure portal |
Because ALDO is a restricted offering, the update is available only to approved customers through an allow-listing process. Organizations cannot pull the update from a public catalog. They must follow Microsoft's guided access procedure.
Deploying and updating these environments has significant prerequisites, including Active Directory Federation Services credentials, DNS configuration, and multiple certificates to secure ingress and management endpoints.
Microsoft has published two guides that take ALDO customers through remediation:
- How to deploy Disconnected Operations for Azure Local
- How to update Disconnected Operations for Azure Local
Both the Azure Resource Manager and Azure Local (build 2604.2.25645) entries in the Security Updates table were released on May 18, 2026.
Affected Systems and Versions
The vulnerability affects Azure Local Disconnected Operations (ALDO) versions 1.0.0 up to, but not including, 2604.2.25645.
Treat any ALDO deployment running a build before 2604.2.25645 as vulnerable. The CVE.org product status listing defines the version boundary.
Azure Resource Manager environments are not affected in practice, because Microsoft has already deployed a server-side mitigation across all Microsoft-operated Azure environments.
Vendor Security History
Microsoft handles vulnerability disclosures through the Microsoft Security Response Center (MSRC), which investigates all reports of security vulnerabilities affecting Microsoft products. The company is also working on its internal security through the Secure Future Initiative (SFI), a multiyear program to improve how Microsoft designs, builds, tests, and operates its products and services.
In the second quarter of fiscal year 2026, Microsoft Cloud revenue reached $51.5 billion, a 26 percent increase, and Azure and other cloud services revenue grew 39 percent. At that scale, vulnerabilities in Azure components, even specialized ones like ALDO, have significant implications for the broader ecosystem.
