CVE-2026-23651 in ACI Confidential Containers
Summary
by MITRE • 03/06/2026
Permissive regular expression in Azure Compute Gallery allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 03/10/2026
The vulnerability identified as CVE-2026-23651 resides within Azure Compute Gallery's implementation where a permissive regular expression is employed in a context that should enforce strict validation. This flaw exists in the authorization and privilege escalation mechanisms that govern local access controls within the compute gallery environment. The issue manifests when legitimate users attempt to perform operations that require elevated privileges, but the system's validation logic fails to properly restrict input parameters through overly permissive pattern matching.
This vulnerability stems from a fundamental flaw in input validation where the regular expression used for parameter sanitization is designed to accept a broader range of inputs than intended. The weakness allows an authorized attacker who already possesses basic access credentials to manipulate input data in a way that bypasses expected validation boundaries. The permissive regex pattern fails to properly constrain the format and content of user-supplied data, creating an opportunity for privilege escalation through carefully crafted inputs that should have been rejected by the system's access control mechanisms.
The operational impact of this vulnerability extends beyond simple unauthorized access as it provides a pathway for attackers to escalate their privileges within the Azure Compute Gallery environment. Once exploited, the vulnerability enables an attacker to gain elevated permissions that would normally require additional authorization steps or administrative credentials. This local privilege escalation capability represents a significant security risk because it allows attackers to operate with higher privileges than their initial access level would permit, potentially leading to data exfiltration, system compromise, or further lateral movement within the Azure infrastructure.
Security practitioners should recognize this vulnerability as a variant of CWE-20, which addresses improper input validation, and it aligns with ATT&CK technique T1068, which covers privilege escalation through local exploits. The vulnerability's exploitation requires an attacker to already possess valid credentials within the system, making it a local privilege escalation issue rather than a remote code execution vulnerability. However, the impact remains severe as it allows for elevation of privileges within the Azure environment where the compute gallery is deployed, potentially affecting virtual machine configurations, access policies, and resource management operations.
Mitigation strategies for this vulnerability should focus on implementing stricter input validation mechanisms that utilize more restrictive regular expressions to ensure that all user-supplied parameters conform to expected formats and ranges. Organizations should immediately update their Azure Compute Gallery implementations to enforce tighter validation controls and monitor for any suspicious privilege escalation activities. Additionally, security teams should implement comprehensive logging and monitoring of access control events to detect anomalous patterns that might indicate exploitation attempts. The recommended approach involves replacing the permissive regex patterns with more precise validation logic that explicitly defines acceptable input parameters and rejects any deviations from the expected format.