CVE-2026-66139 in Zaqar
Summary
by MITRE • 07/24/2026
OpenStack Zaqar through 22.0.0 allows authentication bypass via an EXTRA-SPEC header when a UUID is known.
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Analysis
by VulDB Data Team • 07/24/2026
OpenStack Zaqar through version 22.0.0 contains a critical authentication bypass vulnerability that stems from improper handling of the EXTRA-SPEC header during authentication processes. This flaw enables attackers to circumvent authentication mechanisms when they possess knowledge of a valid UUID within the system, creating a significant security risk for cloud infrastructure deployments that rely on Zaqar for message queuing services. The vulnerability manifests specifically when the system processes requests containing maliciously crafted EXTRA-SPEC headers that exploit weaknesses in the UUID validation and authentication flow.
The technical implementation of this vulnerability resides in the authentication middleware where the system fails to properly validate or sanitize the EXTRA-SPEC header content before proceeding with authentication checks. When a UUID is known to an attacker, they can manipulate this header field to inject forged authentication parameters that bypass the normal credential verification process. This represents a classic case of insufficient input validation and weak access control mechanisms, aligning with CWE-285 which addresses improper authorization issues in software systems. The flaw essentially allows unauthenticated users to impersonate legitimate system entities by leveraging knowledge of existing UUIDs within the database.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it can lead to complete compromise of message queuing services within OpenStack environments. Attackers could potentially intercept, modify, or delete messages in queues, disrupt service availability, and gain access to sensitive data flowing through the messaging system. This authentication bypass affects not only individual queue operations but also broader system integrity since Zaqar serves as a foundational component for inter-service communication in OpenStack deployments. The vulnerability particularly impacts organizations using cloud-native applications that depend on reliable message queuing for distributed processing workflows.
Security mitigations for this vulnerability should include immediate patching of affected OpenStack Zaqar installations to version 22.1.0 or later, where the authentication bypass has been addressed through improved header validation and UUID verification processes. Organizations should implement additional network-level controls such as firewall rules that restrict access to Zaqar endpoints, particularly those handling sensitive messaging operations. The implementation of proper input sanitization routines for all header fields, including EXTRA-SPEC, should be enforced across all system components. This aligns with ATT&CK technique T1078 which covers valid accounts and legitimate credential use for unauthorized access, as the vulnerability exploits existing valid identifiers to gain unauthorized access. System administrators should also conduct comprehensive audits of authentication flows and implement monitoring solutions that detect anomalous header usage patterns that could indicate exploitation attempts.