CVE-2026-113597 in Blinko
Summary
by MITRE • 10/20/2026
Blinko through 1.8.8 contains an insecure direct object reference vulnerability in the tag tRPC router that allows authenticated users to read and modify other users' tags by supplying arbitrary tag IDs. Attackers can enumerate sequential IDs via fullTagNameById, updateTagIcon, and updateTagOrder to reveal private note topics and tamper with tag icons and ordering.
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Analysis
by VulDB Data Team • 10/20/2026
The vulnerability identified in Blinko versions through 1.8.8 represents a classic case of an insecure direct object reference within the application's tRPC router layer. This architectural flaw allows authenticated users to interact directly with server-side resources by manipulating input parameters, specifically tag identifiers, without adequate authorization checks. In a secure implementation, the system should verify that the requesting user has ownership or explicit permission for the specific resource being accessed. However, in this instance, the application relies on client-supplied IDs to locate data objects and performs operations such as reading metadata or modifying attributes based solely on these inputs. This lack of server-side validation creates a significant security gap where identity verification is decoupled from access control decisions, enabling unauthorized actors to traverse the database of tags belonging to other users.
The operational impact of this vulnerability is substantial, affecting both confidentiality and integrity within the application. By exploiting functions such as fullTagNameById, updateTagIcon, and updateTagOrder, an attacker can enumerate sequential tag IDs to discover private note topics that are intended to be hidden from other users. This enumeration capability effectively bypasses any UI-level restrictions or privacy settings configured by the user base. Furthermore, the ability to modify tag icons and reorder tags allows for tampering with the organizational structure of other users' workspaces. An attacker could potentially disrupt a victim's workflow by altering visual cues or reorganizing their data in ways that cause confusion or hide critical information. This level of access undermines the trust model of the application, as authenticated status alone is insufficient to guarantee isolation between user accounts.
From a classification perspective, this vulnerability aligns with CWE-639, which defines Insecure Direct Object References. The attack vector leverages predictable identifiers, likely sequential integers or easily guessable strings, allowing for systematic enumeration rather than requiring complex exploitation techniques. This behavior also maps closely to MITRE ATT&CK technique T1078, specifically the Valid Accounts subcategory, as it relies on legitimate authentication credentials but abuses them to access unauthorized resources. The ability to read private data corresponds to information disclosure principles found in CWE-200, while the modification of tag properties falls under integrity violations described by CWE-913 or CWE-650 depending on whether the focus is on improper control of configuration settings or direct manipulation of objects.
Mitigation strategies must prioritize implementing robust authorization checks at every point where external input interacts with internal data structures. Developers should enforce object-level access controls that verify the relationship between the authenticated user session and the requested resource ID before processing any request. Instead of relying solely on sequential IDs, consider using opaque identifiers such as UUIDs to make enumeration significantly more difficult for attackers. Additionally, implementing rate limiting on API endpoints can help mitigate automated scanning attempts used to discover valid tag IDs. Regular security testing, including penetration tests focused on broken access control scenarios, is essential to ensure that these safeguards remain effective against evolving attack techniques.