CVE-2026-1237 in juju
Summary
by MITRE • 01/28/2026
Vulnerable cross-model authorization in juju. If a charm's cross-model permissions are revoked or expire, a malicious user who is able to update database records can mint an invalid macaroon that is incorrectly validated by the juju controller, enabling a charm to maintain otherwise revoked or expired permissions. This allows a charm to continue relating to another charm in a cross-model relation, and use their workload without their permission. No fix is available as of the time of writing.
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Analysis
by VulDB Data Team • 01/28/2026
The vulnerability described in CVE-2026-1237 represents a critical authorization flaw within the juju orchestration platform that undermines the fundamental security model governing cross-model charm relationships. This issue specifically targets the macaroon-based authentication system that juju employs to manage permissions between different model deployments. When cross-model permissions are revoked or expire as part of normal security operations, the system fails to properly validate the authenticity of macaroons that may have been minted by malicious actors. The vulnerability stems from insufficient validation mechanisms that allow crafted macaroons to bypass the normal authorization checks, effectively creating a persistent backdoor for unauthorized access. This represents a significant deviation from standard security practices where revoked credentials should immediately lose their validity and be rejected by the system.
The technical implementation of this vulnerability exploits the gap in the macaroon validation process within the juju controller's authorization subsystem. An attacker who can manipulate database records gains the capability to generate invalid macaroons that appear legitimate to the juju controller's validation logic. This flaw operates at the intersection of authentication and authorization, where the system's trust model is compromised through the manipulation of cryptographic tokens. The vulnerability's impact extends beyond simple access control to encompass the potential for privilege escalation and unauthorized data access within cross-model deployments. The flaw demonstrates a failure in the principle of least privilege, where legitimate security controls designed to revoke access are circumvented through database manipulation techniques that should not be possible in a properly secured environment.
The operational consequences of this vulnerability are severe and far-reaching for organizations relying on juju for cloud orchestration and model management. Once exploited, the malicious user can maintain access to cross-model relations that should have been terminated, allowing unauthorized charms to continue communicating and sharing resources with other deployed services. This creates a persistent threat vector where compromised permissions can be maintained indefinitely, even after proper revocation procedures have been executed. The vulnerability essentially undermines the entire cross-model security architecture, enabling attackers to maintain unauthorized relationships between charms and potentially access sensitive workloads and data. Organizations using juju for multi-tenant or multi-environment deployments face significant risks as this flaw can be exploited to gain unauthorized access to services in other models without proper authorization.
This vulnerability aligns with CWE-284, which addresses improper access control in software systems, and demonstrates characteristics consistent with ATT&CK technique T1548.001 related to abuse of cloud credentials and unauthorized access. The lack of available fixes at the time of reporting indicates a critical gap in the security maintenance process for the juju platform, leaving organizations with no immediate remediation options. The vulnerability's persistence and the absence of a patch create an extended window of exposure for affected systems, requiring organizations to implement compensating controls and monitoring procedures. Security teams must develop detection mechanisms to identify potentially compromised macaroons and monitor for unauthorized cross-model relationships that may indicate exploitation attempts. The situation represents a high-risk scenario where organizations must balance operational continuity with security posture, as the vulnerability affects core platform functionality while remaining unpatched.
Organizations affected by this vulnerability should implement immediate monitoring and detection measures to identify unauthorized cross-model activities and macaroon usage patterns that deviate from normal operational behavior. The absence of a fix requires defensive measures including enhanced database access controls, regular auditing of cross-model relations, and implementation of manual authorization checks that bypass the vulnerable validation logic. Security operations should establish procedures for identifying and isolating potentially compromised charms that may be maintaining unauthorized relationships through the manipulated macaroons. The vulnerability highlights the importance of maintaining multiple layers of security controls and the risks associated with relying on single-point authentication mechanisms that can be circumvented through database manipulation. Organizations should also consider implementing network segmentation and access controls that limit the potential impact of such exploitation attempts on their broader infrastructure.