CVE-2022-29159 in Deck
Summary
by MITRE • 05/20/2022
Nextcloud Deck is a Kanban-style project & personal management tool for Nextcloud. In versions prior to 1.4.8, 1.5.6, and 1.6.1, an authenticated user can move stacks with cards from their own board to a board of another user. The Nextcloud Deck app contains a patch for this issue in versions 1.4.8, 1.5.6, and 1.6.1. There are no known currently-known workarounds available.
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Analysis
by VulDB Data Team • 05/27/2022
The vulnerability CVE-2022-29159 represents a critical authorization flaw within the Nextcloud Deck application that undermines the fundamental security boundaries between user accounts. This issue affects versions prior to 1.4.8, 1.5.6, and 1.6.1, creating a privilege escalation scenario where authenticated users can manipulate data across arbitrary user boards. The vulnerability specifically targets the stack movement functionality within the Kanban-style project management interface, allowing malicious actors to transfer cards and stacks between their own boards and those belonging to other users. This represents a direct violation of the principle of least privilege and data isolation that security-conscious applications must maintain. The flaw exists in the access control mechanisms that should prevent users from modifying content they do not own or have explicit authorization to manipulate.
The technical implementation of this vulnerability stems from insufficient input validation and authorization checks within the deck application's API endpoints. When users attempt to move stacks between boards, the application fails to properly verify whether the originating board belongs to the authenticated user or if the destination board is accessible to the current user. This oversight creates an opportunity for privilege escalation through unauthorized data manipulation. The vulnerability manifests as a lack of proper board ownership verification during stack movement operations, allowing authenticated users to bypass normal access controls. According to CWE classification, this corresponds to CWE-285: Improper Authorization, which specifically addresses scenarios where systems fail to properly enforce access control policies. The flaw demonstrates a classic case of insufficient authorization checks where the application assumes that authenticated users can perform operations on any board they encounter in the system.
The operational impact of CVE-2022-29159 extends beyond simple data manipulation to potentially compromise the integrity and confidentiality of user information within Nextcloud environments. An attacker with valid credentials could systematically move cards between their own boards and those of other users, potentially disrupting workflow processes, accessing sensitive information, or creating false records. This vulnerability particularly affects collaborative environments where multiple users share the same Nextcloud instance, as it enables one user to interfere with another's project management data. The ability to move cards between boards could be exploited to manipulate task assignments, alter deadlines, or hide critical information from other team members. Organizations relying on Nextcloud Deck for project management and collaboration could experience significant operational disruption, with the potential for data corruption, workflow interference, and unauthorized information access. This vulnerability also aligns with ATT&CK technique T1078.004: Valid Accounts - Cloud Accounts, as it leverages legitimate user credentials to perform unauthorized actions within the system.
Organizations should immediately implement the vendor-provided patches for Nextcloud Deck versions 1.4.8, 1.5.6, and 1.6.1 to remediate this vulnerability. The patch addresses the core authorization issue by implementing proper board ownership verification before allowing stack movement operations. Security administrators should conduct comprehensive audits of their Nextcloud installations to ensure all affected versions have been updated. Additional mitigations include implementing network-level access controls to limit exposure, monitoring for unusual stack movement activities, and reviewing user access permissions to minimize potential impact. The vulnerability demonstrates the critical importance of proper access control implementation in collaborative applications and highlights the need for regular security assessments of third-party components within cloud environments. Organizations should also consider implementing automated patch management solutions to prevent similar vulnerabilities from accumulating in their infrastructure.