CVE-2026-119659 in Blossom
Summary
by MITRE • 10/30/2026
Blossom through 1.17.1 contains an authorization bypass vulnerability that allows authenticated users to access other users' folders because FolderService queries filter only on folder id. Attackers can supply another user's folder id to /folder/info, /folder/upd, /folder/open or /folder/del to read storage paths, rename, toggle visibility, or delete folders.
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Analysis
by VulDB Data Team • 10/30/2026
The vulnerability identified in Blossom versions through 1.17.1 represents a critical failure in server-side access control mechanisms, specifically categorized under CWE-284 Improper Access Control. This flaw manifests as an authorization bypass that permits authenticated users to interact with resources belonging to other accounts within the application ecosystem. The root cause lies in the implementation of the FolderService component, which relies exclusively on the folder identifier for query filtering during API requests. By neglecting to validate whether the requesting user possesses ownership or appropriate permissions for the specified resource, the system fails to enforce proper isolation between distinct user contexts. This architectural oversight allows an attacker who has valid credentials for one account to manipulate data associated with another account simply by substituting the target folder identifier in their request parameters.
The operational impact of this vulnerability is significant as it compromises the confidentiality and integrity of stored files across multiple user accounts. An authenticated adversary can exploit endpoints such as /folder/info, /folder/upd, /folder/open, or /folder/del to perform a range of malicious actions against victim folders. Specifically, by supplying another user's folder id, an attacker can read sensitive storage paths contained within the target directory, potentially exposing file locations and metadata that could facilitate further attacks. Furthermore, the ability to rename folders allows for social engineering tactics where files are disguised or moved to obscure their origin. The capability to toggle visibility alters the accessibility of resources without necessarily changing permissions, while the power to delete folders results in permanent data loss and denial of service conditions for legitimate users. These actions collectively undermine trust in the platform's security posture and can lead to substantial business disruption or regulatory non-compliance depending on the nature of the stored data.
From a threat modeling perspective, this vulnerability aligns with MITRE ATT&CK techniques related to lateral movement and data exfiltration within cloud environments. The ability to access unauthorized resources via API endpoints is characteristic of Broken Object Level Authorization (BOLA), formerly known as Insecure Direct Object References (IDOR). Attackers can automate the enumeration of folder identifiers or leverage previously discovered IDs from logs, network traffic, or client-side code to systematically target other users' data. This type of vulnerability often goes undetected by standard perimeter defenses because it occurs within authenticated sessions and utilizes legitimate API structures, making it difficult for Web Application Firewalls to distinguish between authorized and unauthorized access attempts without deep semantic analysis of the request context relative to user privileges.
Mitigation strategies must focus on implementing robust server-side authorization checks at every point where resource identifiers are processed. Developers should modify the FolderService logic to ensure that all API endpoints verify not only the existence of the requested folder but also its association with the authenticated session's principal identity. This involves querying a relationship table or database field that links folders to their respective owners and rejecting any request where this linkage does not match the current user context. Additionally, implementing principle of least privilege ensures that users can only perform actions on resources they explicitly own or have been granted permission to access. Regular security code reviews focusing on object-level authorization patterns are essential to prevent similar flaws in other parts of the application. For existing deployments, applying the vendor-provided patch for version 1.17.2 and above is required to resolve this issue immediately.